html-css-bootstrap-javascript-and-jquery

HTML, CSS, Bootstrap, Javascript and
jQuery
Meher Krishna Patel
Created on : Octorber, 2017
Last updated : October, 2018
More documents are freely available at PythonDSP

Table of contents
Table of contents i
1 HTML 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 First code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Basic tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.1 Attribute ‘name’ and ‘value’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.2 Core attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6 Text formatting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.7 Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.8 Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.9 Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.10 Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Cascading Style Sheets (CSS) 15
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.1 Inline CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.2 Embedded CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.3 External CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2 Basic CSS Selectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3 Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4 More selectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.4.1 Attribute selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.5 More properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3 Bootstrap 22
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.1 Download and include ﬁles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.2 Add CDN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2.3 Check setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 Grid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.3.1 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.3.2 Nested columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.3.3 Oﬀset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.4 Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.4.1 Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.4.2 Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.4.3 Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.4.4 Horizontal form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.4.5 Form elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
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Table of contents
3.4.6 Control size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.4.7 More buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.4.8 Input group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.4.9 Navigation bar (navbar) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4 JavaScript 45
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.2 First code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.2.1 JavaScript in HTML file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.3 Keywords, Datatypes, Variables and Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.3.1 Keywords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.3.2 Datatypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.3.3 Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.3.4 Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.3.5 String to number conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.3.6 Convert to integer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.3.7 Convert to float . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.3.8 Math . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.3.9 String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.3.10 Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.4 Control structure, loops and functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.4.1 If-else . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.4.2 Switch-case-default . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.4.3 For loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.4.4 While loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.4.5 do-while . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.4.6 for-in loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.4.7 Continue and break . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.4.8 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.5 Event handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5 jQuery 56
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
5.1.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
5.1.2 Add contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.2 jQuery examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.2.1 Add jQuery code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.2.2 jQuery in separate file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.2.3 Get input from user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.3 Selectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.3.1 Select elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.3.2 Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
5.4 Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
5.5 Event handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
ii PythonDSP

Chapter 1
HTML
1.1 Introduction
In this chapter, various component of HTML are discussed to design a web page.
The basic structure for an HTML page is shown below.
• Entries inside the /< . . . /> are known as tags. Most of the tags has an opening and closing e.g. <head>
(opening head) and </head> (closing head). Some of the tags do not have closing tags e.g. <!DOCTYPE
. . . > and <br />. We need to write the HTML codes inside the tags.
• The comments are written between ‘<!–’ and ‘–>’.
• Here Line 1 gives the details of the ‘HTML version’ to the web-browser. The ‘html’ tells it is version 5.
• The ‘head’ tag (Lines 3-5) contains the header related tags e.g. ‘title for the page’ and ‘links for the css ﬁles’
etc.
• The ‘body’ tag (7-11) contains the actual HTML code which is displayed on the web-browser. Also, we add
all the JavaScript related codes just before the closing body tag (</body>).
1 <!DOCTYPE html> 
2 <html> 
3 <head>
4 
5 </head>
6
7 <body>
8 
9
10 
11 </body>
12 </html>
1.2 First code
In below code, the message “Hello World” is displayed on the HTML page. The Fig. 1.1 is the resultant HTML
page.
• The title (Line 4) appears on the top of the browser.
• The tag <h1> is called ‘header’ tag, which has the larger size than the normal text (see the size of ‘Hello
World!’).
• The tag <p> is called the ‘paragraph’ tag, which can be used to write the paragraphs.
<!DOCTYPE html>
<html>
(continues on next page)
1

1.3. Basic tags
(continued from previous page)
<head>
<title>HTML Tutorial</title>
</head>
<body>
<h1> Hello World! </h1>
<p> This is the first HTML code </p>
</body>
</html>
Fig. 1.1: First code
1.3 Basic tags
• The Table 1.1 shows the list of tags which are required for writing the basic ‘HTML’ codes i.e. without any
style e.g. bold, italics and numbering etc.
Table 1.1: List of basic tags
Tag Description Example
h1, . . . , h6 Header tag h1 to h6 <h2> Hi </h2>
p paragraphs (Line changes at the end) <p> Hi </p>
span No line change after span <span>Hi</span> Bye.
div make division between contents <div> . . . </div>
a hyperlink see Section 1.9
center Move content to center <center> Hi </center>
br Line break (no closing tag) <br /> or <br>
hr horizontal line (no closing tag) <hr /> or <hr>
pre preserve formatting <pre> . . . . </pre>
table insert table see Section 1.5
• Let’s see the example of each of these tags,
Note: All the new codes are added below the previous codes in the ‘body’ tag. Therefore only newly added
codes are shown in the tutorial.
<h2> Heading 2 </h2>
<h6> Heading 6 </h6>
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Chapter 1. HTML
<p> This is paragraph </p>
<span> This is span.</span>
<span> The 'br' tag is used after span to break the line </span>
<br/>
<div style="color:blue;">
The 'div' tag can be used for formatting the tags inside it at once using 'style' and 'classes'␣
˓→etc.
<p> This paragraph is inside the 'div' tag </p>
<span> This span is inside the 'div' tag </span>
<br/>
</div>
<center>
<h3> Heading 3 is centered</h3>
<p><span> Centered span inside the paragraph.</span><p>
</center>
Two horizontal line is drawn using two 'hr' tag.
<hr />
<hr>
<pre> 'pre' tag preserve the formatting (good for writing codes)
# Python code
x = 2
y = 3
print(x+y)
</pre>
• Fig. 1.2 is the output of above code. Read the text to understand each tag,
Fig. 1.2: Basic tags : Attribute ‘style’ is used in ‘div’ tag
3 Meher Krishna Patel

1.4. Attributes
1.4 Attributes
In Fig. 1.2, we saw an example of attribute (i.e. style) which changed the color of all the elements to ‘blue’ inside
the ‘div’ tag.
1.4.1 Attribute ‘name’ and ‘value’
• Attribute is defined inside the opening part of a ‘tag’. For example, in the below code, the attribute ‘style’
is defined inside the ‘div’ tag.
<div style="color:blue;">
</div>
• An attribute has two parts i.e. ‘name’ and ‘value’. For example, in the above code, name and value of
the attribute are ‘style’ and ‘blue’ respectively.
1.4.2 Core attributes
Below are the three core attributes which are used frequently in web design.
• id : The ‘id’ is the unique name which can be given to any tag. This is very useful in distinguishing the
element with other elements.
<p id='para1'> This is paragraph with id 'para1' </p>
<p id='para2'> This is paragraph with id 'para2' </p>
• class : The attribute ‘class’ can be used with multiple tags. This is very useful in making groups in HTML
design.
<p class="c_blue"> This is paragraph with class 'blue'</p>
<span class="c_blue"> This is span with class 'blue'</span>
• style : We already see the example of style attribute, which can be used to change the formatting of the
text in HTML design. We can specify various styles which are discussed in Chapter 2.
<p style="font-weight:bold; color:red;">Style attribute is used to bold and color</p>
Note: Above three attributes are used with ‘CSS (cascading style sheet)’ and JavaScript/jQuery, which are the
very handy tools to enhance the look and functionalities of the web-page respectively. The CSS is discussed in
Chapter 2, whereas JavaScript and jQuery are discussed in Chapter 4 and Chapter 5 respectively.
• Also we can define multiple attributes for one tag as shown below,
<p class="my_class" id="para_with_class" style="color:green"> Multiple attributes </p>
• The other useful attributes are listed in Table 1.2
Table 1.2: List of attributes
Name Values Description
id user defined names <p id=’p_1’> Hi </p>
class user defined names <p class=’p_class’> Hi </p>
style CSS styles <p style=”color:red; font-weight:bold;”> Hi </p>
align left, right, center horizontal alignment
width numeric value or % value width of images and tables etc.
height numeric value height of images and tables etc.
4 PythonDSP

Chapter 1. HTML
1.5 Tables
In this section, we will learn to draw tables along with some attributes which are discussed in Table 1.2. Table 1.3
shows the list of tags available to create the table, which are used in Listing 1.1.
Table 1.3: Tags and attributes for creating tables
Tag Description
table beginning and end of table
tr row of table
th header cell
td data cell
Attributes
rowspan number of rows to merge
colspan number of columns to merge
border width of border
cellpadding width of whitespace between two border
cellspacing width of whitespace within a border
bgcolor background color
bordercolor color of border
width width of table (numeric or %)
height height of table (numeric)
caption caption for table
• Some of the attributes of Table 1.3 are used in below example,
Listing 1.1: Table with border and color
1 
2 <table border="1" bordercolor="black" width="450" height="100">
3 <caption>Table 1 : Various tags of table</caption>
4 <tr bgcolor="red" > 
5 <th>Column 1</th> 
6 <th>Column 2</th>
7 <th>Column 3</th>
8 </tr>
9
10 <tr bgcolor="cyan"> 
11 <td>Data 1</td> 
12 <td>Data 2</td>
13 <td>Data 3</td>
14 </tr>
15
16 <tr bgcolor="yellow"> 
17 <td colspan="2">New Data 1</td> 
18 <td>New Data 2</td> 
19 </tr>
20 </table>
21
22
23
24 
25 <table border="1" bordercolor="black" width="80%" height="100">
26 <caption> Table 2 : Width is 80%</caption>
27 <tr bgcolor="red" >
28 <th>Column 1</th>
31 </tr>
32

1.6. Text formatting
33 <tr bgcolor="cyan"> 
34 <td>Data 1</td> 
35 <td>Data 2</td>
36 <td>Data 3</td>
37 </tr>
38
39 </table>
• Fig. 1.3 is the output of above code,
Fig. 1.3: Table generated by Table 1.3
1.6 Text formatting
In this section, we will see some of the text formatting options (see Table 1.4) e.g. bold, italic, subscript and strike
etc.
Table 1.4: Text formatting
Tag Description
b bold
i italic
u, ins underline
strike, del strike
sup superscript
sub subscript
big big size text
small small size text
• Below are the some of the examples of text formatting, whose results are shown in Fig. 1.4,

<p>This is <b>bold</b> text</p>
<p>This is <strike>striked</strike> text</p>
<p>This is <sub>subscript</sub> text</p>
1.7 Images
Image tag has two important attribues i.e. ‘src’ and ‘alt’ as described below,
• src : tells the location of ‘image’ ﬁle e.g. in Line 2 the image ‘logo.jpg’ will be searched inside the folder
‘img’.
6 PythonDSP

Chapter 1. HTML
Fig. 1.4: Text formatting
• alt : is the ‘alternate text’ which is displayed if image is not found. For example, in Line 6, the name of the
image is incorrectly written i.e. ‘logoa’ (instead of ‘logo’), therefore the value of ‘alt’ i.e. ‘Missing Logo.jpg’
will be displayed as shown in Fig. 1.5.
1 
2 <img src="img/logo.jpg" alt="Logo.jpg" width="20%"/>
3
4 <br/> <br/>
5
6 <img src="img/logoa.jpg" alt="Missing Logo.jpg" width="20%"/>
Fig. 1.5: Images
Note: We can use other attributes as well e.g. ‘height’, ‘align’ and ‘border’ etc.

1.8. Lists
1.8 Lists
There are three type of lists in HTML,
• Unordered list : bullet are used in it (see Lines 2 and 9)
• Ordered list : numbers are used in it (see Lines 15, 22 and 28)
• Deﬁnition list : This can be used for writing deﬁnitions in HTML (see Line 35)
1 
2 
3 <ul> Unordered List
4 <li>Pen</li>
5 <li>Pencil</li>
6 <li>Eraser</li>
7 </ul>
8
9 <ul type="circle"> Change bullets : 'square', 'circle' or 'disc'
10 <li>Pen</li>
11 <li>Pencil</li>
12 <li>Eraser</li>
13 </ul>
14
15 
16 <ol> Ordered List
17 <li>Pen</li>
18 <li>Pencil</li>
19 <li>Eraser</li>
20 </ol>
21
22 <ol type='i'> Change style : 'i', 'I', '1', 'a' or 'A'
23 <li>Pen</li>
24 <li>Pencil</li>
25 <li>Eraser</li>
26 </ol>
27
28 <ol type='i' start="5"> Start from 'v'
29 <li>Pen</li>
30 <li>Pencil</li>
31 <li>Eraser</li>
32 </ol>
33
34 
35 <dl>
36 <dt> <h4>HTML Definition List</h4> </dt>
37 <dd> HTML is easy </dd>
38 <dd> HTML is good </dd>
39 <dl>
The outputs of above codes are shown in Fig. 1.6,
1.9 Links

<p>Go to paragraph with<a href="#para1"> id='para1'</a></p>
<a href="http://pythondsp.readthedocs.io"> PythonDSP </a>
<br>
<p><a href="js.html" target="_self"> JavaScript Tutorial</a> in same window.</p>
<p><a href="js.html" target="_blank"> JavaScript Tutorial</a> in new Window.</p>
8 PythonDSP

Chapter 1. HTML
Fig. 1.6: Lists

1.10. Forms
<p><a href="http://pythondsp.readthedocs.io/pdf">Download PDF, DOC or Zip Files</a></p>
<p><a href="mailto:pythondsp@gmail.com">Email me</a></p>
<p><a href="mailto:pythondsp@gmail.com?subject=Feedback&body=Your feedback here">Feeback email</a></p>
Note: We can change the color of the links using ‘alink (active link)’, ‘link’ and ‘vlink (visited link’, by deﬁning
these attributes in the ‘body tag’ as shown below,
<body alink="green" link="blue" vlink="red">
1.10 Forms
Forms can have diﬀerent types of controls to collect the input-data from users, which are listed below and shown
in Table 1.5,
• Text input
• Text area
• Radio button
• Checkbox
• Select box
• File select
• Buttons
• Submit and reset buttons
• Hidden input
10 PythonDSP

Chapter 1. HTML
Table 1.5: List of control inputs and their attributes
Control Attributes Values Description
Input : text type text, password
value user-defined initial value in the area
name user-defined name send to server
size numeric value width of the text area
maxlength numeric value maximum number of characters
Input : radio type radio
value user-defined value value of the button if selected
checked check the button by default
Input : check box type checkbox
value user-defined value value of the box if selected
checked check the box by default
Input : button type button trigger client side script
submit submit the form and run ‘action’
reset reset form
image create image button
method get, post get or post method
action user-defined action to perform on submit
Input : hidden type hidden will not display on html, but can be used
for sending information to server
Selection box name user-defined name send to server
size numeric value enables scroll (default dropdown)
multiple numeric value select multiple items
value user-defined value value of the item if selected
selected select item by default
Text area rows, cols numeric value number of rows and cols
• Below are the exmaple of the control inputs described in Table 1.5

<form>
<h4>Text input </h4>
Name : <input type="text" name="user_name" size="4" value="e.g. meher21" maxlength="10"><br>
Password : <input type="password" name="user_pass" ><br>
<h4> Radio button: name should be same</h4>
<input type="radio" name="r_gender"> Male
<input type="radio" name="r_gender"> Female
<input type="radio" name="r_gender" checked> Infant
<h4> Check box : name should be different</h4>
<input type="checkbox" name="c_male" checked> Male
<input type="checkbox" name="c_female"> Female
<input type="checkbox" name="c_infant"> Infant
<h4> Select box : drop-down</h4>
<select name="s_box">
<option value="s_male">Male</option>
<option value="s_female" selected>Female</option>
<option value="s_infant">Infant</option>
</select>
<h4> Select box : scroll</h4>

1.10. Forms
<select name="s_box" size="4" multiple>
<option value="s_male" selected>Male</option>
<option value="s_female" selected>Female</option>
<option value="s_infant">Infant 1</option>
<option value="s_infant" selected>Infant 2</option>
</select>
<h4> Text area</h4>
<textarea rows="10" cols="80" name="txt_area">Initial Text
x = 2
y = 3
</textarea> 
</form>
Fig. 1.7 is the output of above code,
• Below is the code which shows the working of various buttons. Note that method and action are deﬁned
in this form, which will be triggered on ‘submit’ button. Lastly, ‘hidden’ option is used in this example.
<form method="get|post" action="jquery.html">
<h4> Buttons and Hidden</h4>
Name : <input type="text" name="user_name" size="4" value="Meher" maxlength="16"><br>
Password : <input type="password" name="user_pass" ><br>
<input type="button" onclick="alert('Hello')" name="b_alert" value="Say Hello"/><br>
<input type="submit" name="b_submit" value="Go to jQuery"/>
<input type="reset" name="b_reset" value="Reset"/><br>
<input type="hidden" name="h_data" value="html_tutorial">
</form>
Fig. 1.8 is the output of above code,
12 PythonDSP

Chapter 1. HTML
Fig. 1.7: Various control inputs for creating form

1.10. Forms
Fig. 1.8: Various buttons and hidden-input in the form
14 PythonDSP

Chapter 2
Cascading Style Sheets (CSS)
2.1 Introduction
CSS is used to enhance the look of the web page. In Section 1.4.2, we saw the attribute ‘style’, which is used for
changing the color of the text. Let’s rewrite the example of ‘style’ as shown in next section.
2.1.1 Inline CSS
• Below code is an example of ‘inline CSS’, where the styles are defined inside the individual tags.
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
6 <title>CSS Tutorial</title>
7
8 </head>
9 <body>
10
11 <h3 style="color:blue"> Heading 1 </h3>
14
15 </body>
16 </html>
In the above code, we have three ‘headings’ with font-color as ‘blue’. Suppose, we want to change the color to red,
then we must go to to individual ‘h3’ tag and then change the color. This is easy in this case, but if we have 100
headings in 5 different ‘html’ files, then this process is not very handy. In such cases, CSS can be quite useful as
shown in next section.
2.1.2 Embedded CSS
In the below code, the style is embedded inside the ‘style’ tag as shown in Lines 8-17. Here, we have defined two
classes i.e. ‘h3_blue (Lines 21-23)’ and ‘h3_red (Lines 26-28)’. Then, the selectors at Lines 9 and 13 targets the
class ‘h3_blue’ & ‘h3_red’, and change the color to blue and red respectively. In this chapter, we will discuss the
selectors (e.g. h3.h3_blue) in more details.
Note:
• In CSS, the comments are written between /* and */.
15

2.1. Introduction
• CSS has three parts,
– Selectors e.g. p, h3.h3_blue
– Properties e.g. color
– Values of properties e.g. red
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7
8 <style type="text/css">
9 h3.h3_blue{ /*change color to blue*/
10 color: blue;
11 }
12
13 h3.h3_red{ /*change color to red*/
14 color:red;
15 }
16 </style>
17
18 </head>
19 <body>
20
21 <h3 class='h3_blue'> Heading 1 </h3>
24
25
26 <h3 class='h3_red'> Heading 1 </h3>
29
30 </body>
31 </html>
• Below is the output of above code,
2.1.3 External CSS
We can write the ‘CSS’ code in different file and then import the file into ‘html’ document as shown in this section.
In this way, we can manage the files easily.
• The ‘CSS’ code is saved in the file ‘my_css.css’ which is saved inside the folder ‘asset/css’.
/* asset/css/my_css.css */
h3.h3_blue{
color: blue;
}
h3.h3_red{
color:red;
}
• Next, we need to import the CSS file into the ‘html’ file as shown in Line 7.
1 
2
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Chapter 2. Cascading Style Sheets (CSS)
Fig. 2.1: Embedded CSS
3 <!DOCTYPE html>
4 <html>
5 <head>
7 <link rel="stylesheet" type="text/css" href="asset/css/my_css.css">
8 </head>
9 <body>
10
14
15
19
20 </body>
21 </html>
2.2 Basic CSS Selectors
There are three types of selectors in CSS,
• Element : can be selected using it’s name e.g. ‘p’, ‘div’ and ‘h1’ etc.
• Class : can be selected using ‘.className’ operator e.g. ‘.h3_blue’.
• ID : can be selected using ‘#idName’ e.g. ‘#my_para’.
We will use following HTML for understanding the selectors,

2.3. Hierarchy
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
6 <title>CSS Selectors</title>
8 </head>
9 <body>
10 <h3>CSS Selectors</h3>
11
12 <p class='c_head'> Paragraph with class 'c_head' </p>
13 <p id='i_head'> Paragraph with id 'i_head' </p>
14
15 </body>
16 </html>
• Below code shows the example of diﬀerent selectors, and the output is shown in Fig. 2.2
1 /* asset/css/my_css.css */
2
3 /*element selection*/
4 h3 {
5 color: blue;
6 }
7
8
9 /*class selection*/
10 .c_head{
11 font-family: cursive;
12 color: orange;
13 }
14
15
16 /*id selection*/
17 #i_head{
18 font-variant: small-caps;
19 color: red;
20 }
Fig. 2.2: Selectors : element, class and id
2.3 Hierarchy
In previous section, we saw the example of selectors. In this section, we will understand the hierarchy of the
styling-operations.
Important: Below is the priority level for the CSS,
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• Priority level :
– ID (highest priority)
– Class
– Element
• If two CSS has same priority, then CSS rule at the last will be applicable.
• Below is the html code with following tags,
– ‘p’ tag
– ‘p’ tag with class ‘c_head’
– ‘p’ tag with class ‘c_head’ and id ‘i_head’
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
6 <title>CSS Selectors</title>
8 </head>
9 <body>
10 <p>Paragraph</p>
11
12 <p class='c_head'> Paragraph with class 'c_head' </p>
13 <p class='c_head' id='i_head'> Paragraph with class 'c_head' and id 'i_head' </p>
14
15 </body>
16 </html>
Below is the CSS code. Let’s understand the formatting of all three ‘p’ tags individually. The results are shown
in Fig. 2.3.
• ‘p’ tag at Line 13 of html : Since, ‘id’ has highest priority, therefore CSS rule for #i_head’ (Line 12) will
not be overridden by Line 24; hence the color is red. Line 13 has ‘p’ tag, therefore ‘font-variant’ rule will be
applied by Line 17. Also, this tag has class ‘c_head’, therefore ‘font’ will be set to ‘cursive’. Hence, the line
is “all-caps with font-cursive in red color”.
• ‘p’ tag at Line 12 of html : Similarly, the ‘head’ tag has higher priority than ‘element’ therefore color of
this line is oranage and font-family is ‘cursive’. Also, Line 17 will make it all caps
• ‘p’ tag at Line 10 of html : Color deﬁned at Line 18 will be overridden by Line 24; hence the color will
be blue. Also, Line 17 will make it all caps.
1 /* asset/css/my_css.css */
2
3 /*class selection*/
4 .c_head{
5 font-family: cursive;
6 color: orange; /*override the blue color*/
7 }
8
9
10 /*id selection*/
11 #i_head{
12 color: red;
13 }
14
16 p {
17 font-variant: small-caps;
18 color: blue;
19 }
20
21

2.4. More selectors
23 p {
24 color: green;
25 }
Fig. 2.3: Priority level for CSS rule
2.4 More selectors
Table 2.1 shows the combinations of selectors to target the various elements of the HTML. Also, some of the
example of ‘Attribute selector’ is shown in this section.
Table 2.1: List of selectors
Selectors Description
h1, p, span etc. element selector
.className class selector
#idName id selector
* Universal selector (selects everything)
h1.className select h1 with class ‘className’
h1#idName select h1 with id ‘idName’
p span descendant selector (select span which is inside p)
p > span child selector (‘span’ which is direct descendant of ‘p’)
h1, h2, p group selection (select h1, h2 and p)
span[my_id] select ‘span’ with attribute ‘my_id’
span[my_id=m_span] select ‘span’ with attribute ‘my_id=m_span’
2.4.1 Attribute selector
• Add below code at the end of the html ﬁle. In these lines ‘custom attributes’ are added (i.e. my_id).

<span my_id='m_span'> Span with attribute 'my_id' with value 'm_span' </span>
<br>
<span my_id='m_span2'> Span with attribute 'my_id' with value 'm_span2' </span>
• These custom attributes can be selected as below,
/*attribute selection*/
span[my_id] { /* select 'span' with attribute 'my_id' */
color: green;
font-weight: bold
20 PythonDSP

}
span[my_id=m_span] { /* select 'span' with attribute 'my_id = m_span' */
color: red;
}
2.5 More properties
Table 2.2 shows the some more important properties which can be used in CSS,
Table 2.2: More CSS properties
Property Syntax Description/possible values
size 20% size = 20%
20px 20 pixel
2em 2*font-size
2mm, 2cm, 2in 2 mm, cm and inch
color names e.g. red, blue, green
hex code (#RRGGBB or #RGB) #FFF000 or #FFF
rgb(num, num, num) rgb(0, 0, 255) or rgb(20%, 10%, 70%)
link a:link a:link {color: red}
a:hover
a:visited
a:active
Font font-family serif, cursive
font-style normal, italic, oblique
font-variant normal, small-caps
font-weight normal, bold, bolder, lighter, 100-900
font-size 10px, small, medium, large etc.
Text color red, #FFF
letter-spacing 10px
word-spacing 10 px
text-align right, left, center
text-decoration underline, overline, line-through, none
text-transform capitalize, uppercase, lowercase, none
white-space pre, normal, nowrap
text-shadow text-shadow:5px 5px 8px red;
Image border ‘1px’, or ‘1px solid blue’
height, width 100px, 20%
Border border-style solid, dashed, dotted, double, none etc.
border-top-style
border-bottom-style
border-left-style
border-right-style
border-width 4px, 4pt
border-bottom-width similarly use ‘top’, ‘left’, ‘right’
border (shortcut) 1px solid blue’
Margin margin, margin-left etc.
Padding padding (top, bottom, left, right) ‘10px 10px 2px 2px’ or ‘10px 2px’
padding-right, padding-left etc.

Chapter 3
Bootstrap
3.1 Introduction
One of the problem with basic HTML design is that the webpage may look different in different browser or device
(e.g. mobile, tablet and laptop). Therefore, we may need to modify the code according to browser or device. The
problem can be easily resolved by using Bootstrap.
Bootstrap is a framework which uses HTML, CSS and JavaScript for the web design. It is supported by all the
major browsers e.g. Firefox, Opera and Chrome etc. Further, Bootstrap includes several predefined classes for
easy layouts e.g. dropdown buttons, navigation bar and alerts etc. Lastly, it is responsive in nature i.e. the layout
changes automatically according to the device e.g. mobile or laptop etc.
3.2 Setup
Bootstrap needs atleast 3 files for its operation which can be downloaded from the Bootstrap website.
• bootstrap.css (Line 7) : This file contains various CSS for bootstrap.
• bootstrap.js (Line 16) : This file contains various JavaScript functionalities e.g. dropdown and alerts etc.
• jQuery.js (Line 17) : This file is the jQuery library which can be downloaded from the ‘jQuery’ website.
It is required for proper working of ‘bootstrap.js’.
3.2.1 Download and include files
These files are downloaded and saved inside the ‘asset’ folder. Next, we need to include these files in the HTML
document as below,
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <title>Bootstrap Tutorial</title>
5
6 
7 <link href="asset/css/bootstrap.min.css" rel="stylesheet">
8 
9
10 </head>
11 <body>
12
13
14 
15 
22

Chapter 3. Bootstrap
16 <script src="asset/js/jquery-3.3.1.min.js"></script>
17 <script src="asset/js/bootstrap.min.js"></script>
18 </body>
19 </html>
3.2.2 Add CDN
Another way to include the files is CDN. In this method, we need not to download the files, but provide the links
to these files, as shown in Lines 8, 17 and 19 of below code. Note that, in this case the code will not work in offline
mode.
1 <!DOCTYPE html>
2 <html>
3 <head>
5
6 
7 
8 <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"␣
˓→integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin=
˓→"anonymous">
10
11 </head>
12 <body>
13
14
16 
17 <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
18 
19 <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-
˓→Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
20 </body>
21 </html>
Note: In this tutorial, we have used the first method i.e. download the files and include in the html document.
3.2.3 Check setup
Let’s write our first code to check the correct setup of the Bootstrap.
Note: We need not to memorize the code for creating the ‘dropdown’ button. All the templates are available on
the Bootstrap website. Copy and paste the code from there and the modify the code according to need as shown
in this tutorial.
1 <!DOCTYPE html>
2 <html>
3 <head>
5
6

3.3. Grid system
9
10 </head>
11 <body>
12
13 <div class="dropdown">
14 <button class="btn btn-success dropdown-toggle" type="button" id="dropdownMenu1" data-toggle=
˓→"dropdown" aria-haspopup="true" aria-expanded="true">
15 Dropdown
16 <span class="caret"></span>
17 </button>
18 <ul class="dropdown-menu" aria-labelledby="dropdownMenu1">
19 <li><a href="#">Action</a></li>
20 <li><a href="#">Another action</a></li>
21 <li><a href="#">Something else here</a></li>
22 <li role="separator" class="divider"></li>
23 <li><a href="#">Separated link</a></li>
24 </ul>
25 </div>
26
31 </body>
32 </html>
The resultant web page is shown in Fig. 3.1,
Fig. 3.1: Click on the ‘Dropdown’ button
3.3 Grid system
Bootstrap divides the each row into 12 columns. Then following commands can be used to specify the width
the columns
• col-lg-4 : It will select 4 columns. Choose any number between 1-12. The ‘lg’ stand for large screen (e.g.
large computer screen).
• col-md-5 : ‘md’ = medium screen
• col-sm-3 : ‘sm’ = small screen
• col-xs-3 : ‘xs’ = extra small screen
• col-lg-offset-4 : skip first 4 columns. Simimlary use ‘md’, ‘sm’ and ‘xs’ with offset
24 PythonDSP

3.3.1 Example
Below is an example of grid system. Read the content of the Lines 13-16 to understand it. The resultant webpage
is shown in Fig. 3.2.
Note:
• For easy visualization, in the below code the CSS code (Lines 9-21) is used to fill the columns with colors
and border.
• The columns (Lines 28-30) should be defined inside the class ‘row’ (Line 27).
• Also, sum of the widths of individual columns should not be greater than 12.
• Lastly, if we use ‘col-md-4’ without defining the ‘lg’, ‘sm’ and ‘xs’, then ‘md’ rule will be applicable to higher
size screen ‘lg’, but not on the lower size screen ‘sm’ and ‘xs’. Similary, if we use ‘sm’ without defining the
‘lg’, ‘md’ and ‘xs’, then rule will be applicable to higher size screen i.e. ‘lg’ and ‘md’ but not on ‘xs’
1 <!DOCTYPE html>
2 <html>
3 <head>
5
6 
10 .col-xs-1, .col-xs-2, .col-xs-3, .col-xs-4, .col-xs-5, .col-xs-6, .col-xs-7, .col-xs-8,
11 .col-sm-1, .col-sm-2, .col-sm-3, .col-sm-4, .col-sm-5, .col-sm-6, .col-sm-7, .col-sm-8,
12 .col-md-1, .col-md-2, .col-md-3, .col-md-4, .col-md-5, .col-md-6, .col-md-7, .col-md-8,
13 .col-lg-1, .col-lg-2, .col-lg-3, .col-lg-4, .col-lg-5, .col-lg-6, .col-lg-7, .col-lg-8 {
14 background-color: green;
15 color: white;
16 font-weight: bold;
17 border: 1px solid red;
18 height: 3em; /*height of the box*/
19 text-align: center; /*vertical center the text*/
20 }
21 </style>
22
23 </head>
24
25 <body>
26
27 <div class="row">
28 <div class="col-md-2 col-xs-4">col-md-2, col-xs-4</div>
31 </div>
32
33
38 </body>
39 </html>
Fig. 3.2: Different grid-size (i.e. 2, 6, 4) for ‘medium’ and ‘large’ screen

3.3. Grid system
Fig. 3.3: Equal grid-size (i.e. 4) for ‘extra small’ and ‘small’ screen
3.3.2 Nested columns
We can further divide a column into small columns by defining a class ‘row (Line 30)’ inside the ‘column’ (Line
29), as shown in Lines 29-34.
1 <!DOCTYPE html>
2 <html>
3 <head>
5
6 
15 color: white;
20 }
21 </style>
22
23 </head>
24
25 <body>
26
29 <div class="col-md-6 col-xs-4">
31 <div class="col-xs-6">col-xs-6</div>
32 <div class="col-xs-6">col-xs-6</div>
33 </div>
34 </div>
36 </div>
37
38
43 </body>
44 </html>
3.3.3 Offset
We can skip the columns using ‘offset’ as shown in Line 27; and the corresponding html page is shown in Fig. 3.4,
26 PythonDSP

1 <!DOCTYPE html>
2 <html>
3 <head>
5
6 
15 color: white;
20 }
21 </style>
22 </head>
23
24 <body>
25
27 <div class="col-md-offset-2 col-md-2">col-md-2</div>
28 <div class="col-md-8">col-md-8</div>
29 </div>
30
31
36 </body>
37 </html>
Fig. 3.4: Oﬀset
3.4 Components
Once we understand the ‘html’, ‘css’ and ‘Bootstrap-grid’ understood, then the use of Bootstrap-components
are straightforward. Just copy and paste the code from the Bootstrap website and modify it according to the
requirement.
In this section, we will use following template.
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap Tutorial</title>

<link href="asset/css/bootstrap.min.css" rel="stylesheet">

</head>

3.4. Components
<body>


<script src="asset/js/jquery-3.3.1.min.js"></script>
<script src="asset/js/bootstrap.min.js"></script>
</body>
</html>
3.4.1 Labels
• The class ‘label’ is used to create the label (Line 11).
• The class ‘label-info’ sets the color of the label to ‘blue’ (Line 11).
• The size of the ‘labels’ can be changes using ‘element’ tags (e.g. ‘h3’ in Line 11) outside the ‘span’ tag (Line
11).
Note: Bootstrap provides 6 color option,
• danger
• default
• info
• primary
• success
• warning
1 <!DOCTYPE html>
2 <html>
3 <head>
5 
8 </head>
9
10 <body>
11 <h3>Example heading <span class="label label-info">New</span></h3>
12 <hr>
13
18 </body>
19 </html>
Fig. 3.5: Label
28 PythonDSP

Note: All the codes will be added in the ‘body’ tag, and the new code will be inserted below the previous codes.
Therefore full HTML code is not added in the tutorial.
3.4.2 Buttons
The element ‘button’ can be used to create the button in Bootstrap as shown below,
Note:
• We can use ‘lg’, ‘md’ and ‘xs’ etc. to set the size of the button.
• In Line 3, a glyphicon is added (i.e. trash sign). More glyphicon can be found on the Boostrap-webpage.
<h3> Buttons </h3>
<button type="button" class="btn btn-primary">Sign in</button>
<button type="button" class="btn btn-danger"> Delete <span class="glyphicon glyphicon-trash"><span></
˓→button>
<button type="submit" class="btn btn-lg btn-success">Submit</button>
<button type="submit" class="btn btn-md btn-success">Submit</button>
<button type="submit" class="btn btn-sm btn-success">Submit</button>
Fig. 3.6: Buttons
3.4.3 Forms
In this section, 4 types of forms are added,
3.4.3.1 Basic form
Output of below code is shown in Fig. 3.7,
<h2> Basic form </h2>
<div class="row">
<div class="col-sm-5" style="background: pink">
<div class="panel-body">
<form role="form">
<div class="form-group">
<label for="exampleInputEmail1">Email address</label>
<input class="form-control" id="exampleInputEmail1" placeholder="Enter email" type="email">
</div>
<label for="exampleInputPassword1">Password</label>
<input class="form-control" id="exampleInputPassword1" placeholder="Password" type="password
˓→">
</div>

3.4. Components
<label for="exampleInputFile">File input</label>
<input id="exampleInputFile" type="file">
<p class="help-block">Example block-level help text here.</p>
</div>
<div class="checkbox">
<label>
<input type="checkbox"> Check me out
</label>
</div>
<button type="submit" class="btn btn-info">Submit</button>
</form>
</div>
</div>
</div>
<br><br>
Fig. 3.7: Basic form
3.4.4 Horizontal form
<h3> Horizontal form </h3>
<div class="row">
30 PythonDSP

<form class="form-horizontal" role="form">
<label for="inputEmail1" class="col-lg-2 col-sm-2 control-label">Email</label>
<div class="col-lg-10">
<input class="form-control" id="inputEmail1" placeholder="Email" type="email">
</div>
</div>
<label for="inputPassword1" class="col-lg-2 col-sm-2 control-label">Password</label>
<input class="form-control" id="inputPassword1" placeholder="Password" type="password">
</div>
</div>
<div class="col-lg-offset-2 col-lg-10">
<label>
<input type="checkbox"> Remember me
</label>
</div>
</div>
</div>
<div class="col-lg-offset-2 col-lg-10">
<button type="submit" class="btn btn-danger">Sign in</button>
</div>
</div>
</form>
</div>
</div>
</div>
3.4.4.1 Inline form
<h2> Inline form </h2>
<div class="row">
<form class="form-inline" role="form">
<label class="sr-only" for="exampleInputEmail2">Email address</label>
<input class="form-control" id="exampleInputEmail2" placeholder="Enter email" type="email">
</div>
<label class="sr-only" for="exampleInputPassword2">Password</label>
<input class="form-control" id="exampleInputPassword2" placeholder="Password" type="password
˓→">
</div>
<label>
<input type="checkbox"> Remember me
</label>
</div>
<button type="submit" class="btn btn-success">Sign in</button>
</form>

3.4. Components
Fig. 3.8: Horizontal form
</div>
</div>
</div>
<br><br>
Fig. 3.9: Inline form
3.4.4.2 Modal form
Modal form appears in the pop-up window. Output of below code is shown in Fig. 3.10,

<h3> Modal form </h3>
<div class="row">
32 PythonDSP

<a href="#myModal" data-toggle="modal" class="btn btn-xs btn-success">
Form in Modal
</a>

<div aria-hidden="true" aria-labelledby="myModalLabel" role="dialog" tabindex="-1" id="myModal"␣
˓→class="modal fade">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button aria-hidden="true" data-dismiss="modal" class="close" type="button">×</
˓→button>
<h4 class="modal-title">Form Tittle</h4>
</div>
<div class="modal-body">

<form role="form">
<label for="exampleInputEmail1">Email address</label>
<input class="form-control" id="exampleInputEmail3" placeholder="Enter email
˓→" type="email">
</div>
<label for="exampleInputPassword1">Password</label>
<input class="form-control" id="exampleInputPassword3" placeholder="Password
˓→" type="password">
</div>
<label for="exampleInputFile">File input</label>
<input id="exampleInputFile3" type="file">
</div>
<label>
<input type="checkbox"> Check me out
</label>
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>

</div>
</div>
</div>
</div>
</div>
</div>
</div>
<hr>
3.4.5 Form elements

3.4. Components
Fig. 3.10: Modal form

<h3> Form elements </h3>
<div class="row">
<form class="form-horizontal tasi-form" method="get">
<label class="col-sm-2 col-sm-2 control-label">Default</label>
<div class="col-sm-10">
<input class="form-control" type="text">
</div>
</div>
<label class="col-sm-2 col-sm-2 control-label">Help text</label>
<span class="help-block">A block of help text that breaks onto a new line and may␣
˓→extend beyond one line.</span>
</div>
</div>
<label class="col-sm-2 col-sm-2 control-label">Rounder</label>
<input class="form-control round-input" type="text">
</div>
</div>
<label class="col-sm-2 col-sm-2 control-label">Input focus</label>
34 PythonDSP

<input class="form-control" id="focusedInput" value="This is focused..." type="text">
</div>
</div>
<label class="col-sm-2 col-sm-2 control-label">Disabled</label>
<input class="form-control" id="disabledInput" placeholder="Disabled input here..."␣
˓→disabled="disabled" type="text">
</div>
</div>
<label class="col-sm-2 col-sm-2 control-label">Placeholder</label>
<input class="form-control" placeholder="placeholder" type="text">
</div>
</div>
<label class="col-sm-2 col-sm-2 control-label">Password</label>
<input class="form-control" placeholder="" type="password">
</div>
</div>
<label class="col-lg-2 col-sm-2 control-label">Static control</label>
<p class="form-control-static">email@example.com</p>
</div>
</div>
</form>
</div>
</div>
</div>
3.4.6 Control size

<h3>Control size</h3>
<div class="row">
<label class="col-sm-2 control-label col-lg-2" for="inputSuccess">Control sizing</label>
<input class="form-control input-lg m-bot15" placeholder=".input-lg" type="text">
<input class="form-control m-bot15" placeholder="Default input" type="text">
<input class="form-control input-sm m-bot15" placeholder=".input-sm" type="text">
<select class="form-control input-lg m-bot15">
<option selected="selected">Option 1</option>
<option>Option 2</option>
</select>
<select class="form-control m-bot15">

3.4. Components
Fig. 3.11: Form elements
36 PythonDSP

</select>
<select class="form-control input-sm m-bot15">
</select>
</div>
</div>
</form>
</div>
</div>
</div>
Fig. 3.12: Form elements
3.4.7 More buttons
<h3>Buttons</h3>
<div class="row">
<label class="col-sm-2 control-label col-lg-2" for="inputSuccess">Checkboxes and␣
˓→radios</label>
<label>
<input value="" type="checkbox">
Option one is this and thatÐbe sure to include why it's great
</label>
</div>

3.4. Components
<label>
<input value="" type="checkbox">
Option one is this and thatÐbe sure to include why it's great option one
</label>
</div>
<div class="radio">
<label>
<input name="optionsRadios" id="optionsRadios1" value="option1" checked=
˓→"checked" type="radio">
Option one is this and thatÐbe sure to include why it's great
</label>
</div>
<div class="radio">
<label>
<input name="optionsRadios" id="optionsRadios2" value="option2" type=
˓→"radio">
Option two can be something else and selecting it will deselect option␣
˓→one
</label>
</div>
</div>
</div>
<label class="col-sm-2 control-label col-lg-2" for="inputSuccess">Inline checkboxes</
˓→label>
<label class="checkbox-inline">
<input id="inlineCheckbox1" value="option1" type="checkbox"> 1
</label>
</label>
</label>
</div>
</div>
<label class="col-sm-2 control-label col-lg-2" for="inputSuccess">Selects</label>
<select id="select-dropdown-num" class="form-control m-bot15">
<option selected="selected">1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
<select multiple="multiple" class="form-control">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
</div>
</div>
38 PythonDSP

<label class="col-sm-2 control-label col-lg-2" for="inputSuccess">Column sizing</
˓→label>
<div class="row">
<input class="form-control" placeholder=".col-lg-2" type="text">
</div>
</div>
</div>
</div>
</div>
</div>
</form>
</div>
</div>
</div>
Fig. 3.13: Buttons
3.4.8 Input group

<h3>Input groups</h3>
<div class="row">
<label class="col-sm-2 control-label col-lg-2">Basic examples</label>
<div class="input-group m-bot15">
<span class="input-group-addon">@</span>
<input class="form-control" placeholder="Username" type="text">
</div>

3.4. Components
<span class="input-group-addon">.00</span>
</div>
<span class="input-group-addon">$</span>
<span class="input-group-addon">.00</span>
</div>
</div>
</div>
<label class="col-sm-2 control-label col-lg-2">Sizing</label>
<div class="input-group input-group-lg m-bot15">
<input class="form-control input-lg" placeholder="Username" type="text">
</div>
</div>
<div class="input-group input-group-sm m-bot15">
</div>
</div>
</div>
<label class="col-sm-2 control-label col-lg-2">Checkboxe and radio</label>
<span class="input-group-addon">
<input type="checkbox">
</span>
</div>
<span class="input-group-addon">
<input type="radio">
</span>
</div>
</div>
</div>
<label class="col-sm-2 control-label col-lg-2">Button addons</label>
<span class="input-group-btn">
<button class="btn btn-white" type="button">Go!</button>
</span>
</div>
40 PythonDSP

<span class="input-group-btn">
<button class="btn btn-white" type="button">Go!</button>
</span>
</div>
<div class="input-group-btn">
<button type="button" class="btn btn-white dropdown-toggle" data-toggle="dropdown
˓→">Action <span class="caret"></span></button>
<ul class="dropdown-menu">
<li><a href="#">Action</a></li>
<li><a href="#">Another action</a></li>
<li><a href="#">Something else here</a></li>
<li class="divider"></li>
<li><a href="#">Separated link</a></li>
</ul>
</div>
</div>
<button type="button" class="btn btn-white dropdown-toggle" data-toggle="dropdown
˓→">Action <span class="caret"></span></button>
<ul class="dropdown-menu pull-right">
</ul>
</div>
</div>
</div>
</div>
<label class="col-sm-2 control-label col-lg-2">Segmented buttons</label>
<button tabindex="-1" class="btn btn-white" type="button">Action</button>
<button tabindex="-1" data-toggle="dropdown" class="btn btn-white dropdown-toggle
˓→" type="button">
<span class="caret"></span>
</button>
<ul role="menu" class="dropdown-menu">
</ul>
</div>
</div>

3.4. Components
<button tabindex="-1" class="btn btn-white" type="button">Action</button>
<button tabindex="-1" data-toggle="dropdown" class="btn btn-white dropdown-toggle
˓→" type="button">
<span class="caret"></span>
</button>
<ul role="menu" class="dropdown-menu pull-right">
</ul>
</div>
</div>
</div>
</div>
</form>
</div>
</div>
</div>
Fig. 3.14: Input groups
3.4.9 Navigation bar (navbar)
For navbar, one more ‘css’ ﬁle is added at Line 8. This CSS will create the space at the top for the ‘navbar’ so that
it will not overlap with the contents of the HTML page. Further, Lines 13-44 adds various links to the navbar.
Lastly, we can add HTML content below Line 46.
1 <!DOCTYPE html>
2 <html>
3 <head>
42 PythonDSP

5 
8 <link href="asset/css/theme.css" rel="stylesheet"> 
9 </head>
10
11 <body>
12
13 <div class="navbar navbar-inverse navbar-fixed-top">
14 <div class="container">
15 <div class="navbar-header">
16 <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-
˓→collapse">
17 <span class="icon-bar"></span>
20 </button>
21 <a class="navbar-brand hidden-sm" href="http://pythondsp.readthedocs.io/">PythonDSP</a>
22 </div>
24 <div class="navbar-collapse collapse">
25 <ul class="nav navbar-nav">
26
27 <li><a href="basic.html">HTML</a></li>
28 <li><a href="css.html">CSS</a></li>
29
30
31 <li class="dropdown">
32 <a href="#" class="dropdown-toggle" data-toggle="dropdown">More<b class="caret"></b></a>
33 <ul class="dropdown-menu">
34 <li><a href="bootstrap.html">Bootstrap</a></li>
35 <li><a href="js.html">Javascript</a></li>
36 <li><a href="jquery.html">jQuery</a></li>
37 </ul>
38 </li>
39
40 </ul>
41 </div>
42 </div>
43 </div>
44 </div>
45
46 
47
52 </body>
53 </html>

3.4. Components
Fig. 3.15: Navigation bar (navbar)
44 PythonDSP

Chapter 4
JavaScript
4.1 Introduction
• JavaScript is a dynamic language which is used for designing the web pages on the client side.
• It is case sensitive language.
• It is untyped language i.e. a variable can hold any type of value.
• // is used for comments.
• ; i used for line termination.
• JavaScript code should be added at the end i.e. just above the closing-body-tag.
• It is better to write the JavaScript code in separate file as shown in next section.
4.2 First code
The JavaScript code can be written in the ‘html’ file or in the separate ‘JavaScript file (.js)’ as shown in this
section,
4.2.1 JavaScript in HTML file
In HTML file, the JavaScript codes can be written inside the ‘script’ tag as shown in Lines 11-13 of below code.
The code will write the message “Hello World from JavaScript!” on the web page. Open the ‘js.html’ in the browser
to see the message.
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
6 <title>JavaScript</title>
7 </head>
8 <body>
9
10
11 <script type="text/javascript">
12 document.write("Hello World from JavaScript!<br>");
13 </script>
14
15 </body>
16 </html>
• Below is the output on the HTML page,
45

4.3. Keywords, Datatypes, Variables and Operators
Hello World from JavaScript!
4.2.1.1 JavaScript in separate file
• The JavaScript code is saved in the file ‘my_javascript.js’ which is located inside the folders ‘asset/js’. Note
that, no ‘script tag’ is used here.
1 // asset/js/my_javascript.js
2
• Next we need to import the .js file in the HTML file as shown below,
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7 </head>
8 <body>
9
10
11
12 
13 <script src="asset/js/my_javascript.js"></script>
14
15 </body>
16 </html>
• Now, open the ‘js.html’ file in the browser and it will display the message.
Note: We will use the second method in this tutorial.
4.3 Keywords, Datatypes, Variables and Operators
4.3.1 Keywords
• Below are the reserved keywords in the JavaScript which can not be used as ‘variable’ and ‘function’ names
etc.
46 PythonDSP

Chapter 4. JavaScript
Table 4.1: List of keywords
Keywords
abstract boolean break byte
case catch char class
const continue debugger default
delete do double else
enum export extends false
final float for function
goto if implements import
in int interface long
native new null package
private protected public return
short static super switch
this throw throws transient
true try typeof var
void volatile while with
4.3.2 Datatypes
JavaScript has three types of data,
• Numbers : 123, 32.32
• Strings : “Meher”, “Krishna Patel”, “123”
• Boolean : true, false
Note: All the numbers are considered as ‘floating point’.
4.3.3 Variables
Variables can be define using keyword ‘var’. Further, JavaScript is untyped language i.e. a variable can hold any
type of value.
• In the below HTML, ‘p’ tag with id ‘p_name’ is defined at Line 10. This id will be used to write some text
using JavaScript,
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7 </head>
8 <body>
9
10 <p id='p_name'></p>
11
14
15 </body>
16 </html>
• Two variables are defined at Lines 9-10 of type ‘string’ and ‘float’ respectively. Then ‘getElementById’
is used to locate the tag with id ‘p_name’ and the text is inserted as shown in Line 11. Lastly, the ‘+’ sign
is used to concatenate the values as Line 11.

1 // asset/js/my_javascript
2
3
4 // print message on the webpage
6
7
8 // variable example
9 var your_name = "Meher";
10 var age = 20;
11 document.getElementById("p_name").innerHTML= "Hello "+ your_name + "<br>Age : " + age;
• Below is the output of above codes. Note that the message ‘Hello World from JavaScript!’ is added at the
end as ‘JavaScript’ file is imported at the end.
Warning: If we import the ‘JavaScript’ file between the ‘ending-head-tag’ and ‘start-body-tag’, then Message
‘Hello Meher . . . ’ will not be displayed as ‘JavaScript’ will execute before the loading of the page; and JavaScript
can not find the id ‘p_name’.
Hello Meher
Age : 20
Hello World from JavaScript!
Note: All the JavaScript/HTML codes will be added below the existing codes, therefore only the newly added
code will be shown in the rest of the tutorial.
• ‘prompt’ can be used to read the values from the user.
// prompt
var x = prompt("enter a number");
document.write("2 * ", x, " = ", 2*x + "<br>");
A pop-up window will appear due to prompt. If we provide the input value as 3, then below output will be
generated,
2 * 3 = 6
Note: The ‘,’ and ‘+’ can be used to combine various outputs as shown in above example
4.3.4 Operators
Various operators are shown in this section. The usage of some of these operators are shown in Section 4.4.
4.3.4.1 Arithmetic operators
• +
• -
• *
• /
• % : modulus i.e remainder of the division
• ++ (increment)
• – (decrement)
48 PythonDSP

4.3.4.2 Assignment operators
• =
• +=
• -=
• *=
• /=
• %=
4.3.4.3 Comparison operators
• == (compare only values not type)
• === (compare both values and type)
• !=
• >
• <
• >=
• <=
4.3.4.4 Conditional operator
• ?:
e.g. ‘( (a > b) ? a/b : b/a) )’ i.e if ‘a>b’ then do ‘a/b’ else do ‘b/a’
4.3.4.5 Logical operators
• && (logical and)
• || (logical or)
• ! (logical not)
4.3.4.6 Bitwise operators
• & (and)
• | (or)
• ^ (xor)
• ~ (not)
4.3.5 String to number conversion
‘Number’ is used to convert the string into numbers.
// string to number conversion
document.write("2 + Number('3.4') = ", 2 + Number('3.4'), "<br>");
Below is the output of above code,
2 + Number('3.4') = 5.4
4.3.6 Convert to integer
A string or ﬂoat value can be converted into integer using ‘parseInt’

// int conversion
document.write("2 + parseInt('3.4') = ", 2 + parseInt('3.4'), "<br>"); // string to int
document.write("2 + parseInt(3.4) = ", 2 + parseInt(3.4), "<br>"); // float to int
Below are the outputs of above code,
2 + parseInt('3.4') = 5
2 + parseInt(3.4) = 5
4.3.7 Convert to float
The ‘parseFloat’ or ‘Number’ can be used to convert the value into float values.
document.write("2 + parseFloat('3.4') = ", 2 + parseFloat("3.4"), "<br>"); // parseFloat
4.3.8 Math
‘Math’ library contains various useful function as shown below,
// math
document.write("pi = ", Math.PI, "<br>");
document.write("e = ", Math.E, "<br>");
document.write("similarly we can use 'abs', 'floor', 'ceil' and 'round' etc. <br>")
document.write("random number : ", Math.ceil(Math.random()*20), "<br>"); // enter random number
Below are the ouputs of above code,
pi = 3.141592653589793
e = 2.718281828459045
similarly we can use 'abs', 'floor', 'ceil' and 'round' etc.
random number : 16
4.3.9 String
Below are the some of the useful ‘string-styles’,
// string
document.write("meher".toUpperCase(), "<br>") // uppercase
w = "Krishna"
document.write(w.toLowerCase(), "<br>") // lowercase
document.write(w.small(), "<br>") // small
document.write(w.bold(), "<br>") // bold
document.write(w.strike(), "<br>") // strike
document.write(w.fontsize("5em"), "<br>") // strike
document.write(w.link("http://pythondsp.readthedocs.io"), "<br>") // link
document.write(w.fontcolor("red").fontsize("12em"), "<br>") // multiple
The outputs are shown in Fig. 4.1
4.3.10 Arrays
In JavaScript, the arrays can store different types of values as shown in below code,
50 PythonDSP

Fig. 4.1: String styles
// arrays
arr = [15, 30, "Meher"]
for(a in arr)
document.write(arr[a], " ");
document.write("<br>");
document.write(arr.pop(), "<br>"); // remove last element
arr.push("Krishna"); // add element to end
document.write(arr.pop(), "<br>");
document.write("lenght of array: ", arr.length, "<br>");
Below are the output of above code,
15 30 Meher
Meher
Krishna
lenght of array: 2
4.4 Control structure, loops and functions
4.4.1 If-else
In the below code, three conditions are checked for the variable ‘age’; and corresponding message is printed.
// asset/js/my_javascript
// if-else
age = 10;
if (age > 3 && age < 6){
document.write("Age : " + age + "<b> go to kindergarten</b>");
}
else if ( age >=6 && age < 18){
document.write("Age : " + age + "<b> go to school</b>");
}
else{
document.write("Age : " + age + "<b> go to college</b>");

4.4. Control structure, loops and functions
}
• Since age is 10, therefore ‘else if’ statement is satisﬁed and we will get below output,
Age : 10 go to school
4.4.2 Switch-case-default
Below is an example of Switch-case-default statement,
// asset/js/my_javascript
// switch-case
var grade = 'A';
document.write("Grade " + grade + " : ");
switch(grade){
case 'A':
document.write("Very good grade!");
break;
case 'B':
document.write("Good grade!");
break;
default: // if grade is neither 'A' nor 'B'
document.write("Enter correct grade");
}
• Below is the output of above code,
Grade A : Very good grade!
4.4.3 For loop
Below code prints the value from 5-0,
// For loop
for (i=5; i>=0; i--){
document.write(i + " ");
}
• Below is the output,
5 4 3 2 1 0
4.4.4 While loop
// While loop
x=0;
while(x < 5){
document.write(x + " ");
x++;
}
52 PythonDSP

4.4.5 do-while
// do-while
x=0;
do{
document.write(x + " ");
x++;
}while(x < 3);
Below is the output,
0 1 2
4.4.6 for-in loop
The ‘for-in’ loop can be used to iterate over the array as shown below,
// for-in loop
arr = [10, 12, 31]; // array
for (a in arr){
document.write(arr[a] + " ");
}
4.4.7 Continue and break
Continue and break statements are used inside the ‘loop’ statements.
• Continue will skip the loop and go to next iteration, if the condition is met. In the below code, 3 will not be
printed at the output.
// continue
for (i=5; i>=0; i--){
if (i==3){ // skip 3
continue;
}
}
Below is the output where 3 is not printed in the output.
5 4 2 1 0
• ‘Break’ statement will quit the loop if the condition is met. In the below code, the for loop will be terminated
at ‘i=3’, therefore only 5 and 4 will be printed,
// break
for (i=5; i>=0; i--){
if (i==3){ // exit loop when i=3
break;
}
}
Below is the output of the above code,

4.5. Event handling
5 4
4.4.8 Functions
In the below code a function ‘add2Num’ is defined which adds the two numbers and returns the result.
// function
function add2Num(num1, num2){ // function definition
return num1 + num2;
}
sum = add2Num(2, 3); // function call
document.write("2 + 3 = " + sum);
Below is the output,
2 + 3 = 5
4.5 Event handling
One of the main usage of JavaScript is ‘event handling’. “Mouse click” and ‘pressing keys on keyboard’ are the
example of ‘events’. With the help of JavaScript, we can perform certain actions at the occurrence of the events,
as shown below.
• ‘alert’ is used to display message in the ‘pop up’ window.
function alertMessage(message){
alert(message)
}
• In Line 13, message ‘Hello’ is shown in the pop-up window on the event ‘onclick’. Note that
“JavaScript:void(0)” is used here, which does not refresh the page.
• Line 15 is same as Line 13, but “JavaScript:void(0)” is not used, therefore page will be refreshed.
• Line 17 calls the function ‘alertMessage’ to display the mesage, which is defined in the above code.
• Lines 19-25 use different events i.e. ‘onmouseover’, ‘onmouseleave’, ‘onmouseup’ and ‘onmousedown’; and
the color and the text of the string changes based on these operations.
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7 </head>
8 <body>
9
10 <p id='p_name'></p>
11
12
13 <a href="JavaScript:void(0)", onclick="alert('Hello')">Say Hello</a><br> 
14
15 <a href="", onclick="alert('Hello')">Say Bye</a><br> 
16
17 <a href="JavaScript:void(0)", onclick="alertMessage('Bye via function')">Bye-function</a><br>
18
19 <a href="JavaScript:void(0)",
54 PythonDSP

20 onmouseover="this.style.color='red'",
21 onmouseleave="this.style.color='blue'",
22 onmouseup="this.text='Not clicked'",
23 onmousedown="this.text='You clicked me'">
24 Not clicked
25 </a><br>
26
27
30
31 </body>
32 </html>
4.6 Conclusion
In this tutorial, we have selected the element with certain ‘id’ using ‘getElementById’. Also, we saw the example
of ‘event handling’ Although, we can use JavaScript for these operations, but it is better to use jQuery for these
purposes, which is discussed in Chapter 5. A good approach is use to the jQuery for ‘selectors’ & ‘event handling’
and then use various features of JavaScript which are described in Section 4.4 to implement the logics.

Chapter 5
jQuery
5.1 Introduction
jQuery is the Javascipt library.
5.1.1 Requirements
• First create a file ‘jQuery.html’. Next, we need three files, i.e. one CSS (Line 9) and two Javascipt (Lines
23-24), for using the jQuery in this tutorial. These files are saved inside the folder ‘asset’, which can be
downloaded from the repository. Lines 9 and 24 are the bootstrap files, whereas Line 23 is the actual
‘jQuery’ file which is required to use the jQuery.
Note: Note that, the ‘jQuery.js’ files should be placed above the ‘bootstrap.js’ file, otherwise the bootstrap-
javascipt will not work.
1 
2
3 <!DOCTYPE html>
4 <html>
5 <head>
6 <title>jQuery</title>
7
8 
10 
11
12 </head>
13 <body>
14
15
16
17
18
19
20
25
26 </body>
27 </html>
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Chapter 5. jQuery
• If we open this html ﬁle in the browser, the a blank page will be displayed with header ‘jQuery’.
5.1.2 Add contents
Next add one jumbotron (Line 15-19) and few labels (Lines 21-26) in the html ﬁle as shown in Fig. 5.1.
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7
8 
11
12 </head>
13 <body>
14
15 <div class="jumbotron">
16 <div class="col-md-offset-4 container">
17 <h1><b>jQuery</b></h1>
18 </div>
19 </div>
20
21 <span class="label label-lg label-default" id="l_default">Default</span>
22 <span class="label label-primary" id="l_primary">Primary</span>
23 <span class="label label-success" id="l_success">Success</span>
24 <span class="label label-info" id="l_info">Info</span>
25 <span class="label label-warning" id="l_warning">Warning</span>
26 <span class="label label-danger" id="l_danger">Danger</span>
27
28
29
30
35
36 </body>
37 </html>
Fig. 5.1: Jumbotron and labels are added

5.2. jQuery examples
5.2 jQuery examples
Following are the important parts for writing a jQuery,
• Selectors : to select the speciﬁc element (e.g. ‘id’, ‘class’ etc.) for operations.
• Event handling : perform some operations (hide, toggle etc.) on the selected items at some events (e.g.
click, mouser over etc.).
In this section, we will see the working of of jQuery with the help of some examples. Then in Section 5.3, we will
see various methods to use the selectors to target the speciﬁc elements. Next, a list of operations are shown in
Table 5.2. Finally in Section 5.5, a list of events are shown which can be used to initiate the operations.
5.2.1 Add jQuery code
Now, we can add the jQuery code as shown in Lines 36-40. Please note the following part,
• $ sign is used to hit the jQuery. In the simple words, we can say that it execute the jQuery.
• The code is written between the following block. This block stops the jQuery to execute until the whole page
is loaded, i.e. jQuery will be executed after completion of the page-download.
$(function() {
// write code here
});
• The above block is a shorthand for below,
$(document).ready(function() {
// write code here
});
Note: We can use multiple blocks, if we want to separate the codes; or we can write all the jQueries within one
block.
• Lastly, the below line hides the id “l_default” after 1000 ms, i.e. ‘Default’ label will not be displayed after
1000 ms as shown in Fig. 5.2
$("#l_default").hide(1000); // hide id = 'l_default' using # operator after 300 ms
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7
8 
11
12 </head>
13 <body>
14
18 </div>
19 </div>
20
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Chapter 5. jQuery
27
28
29
30
35
37 $(function() {
38 $("#l_default").hide(1000); // hide id = 'l_default' using # operator after 300 ms
39 });
40 </script>
41 </body>
42 </html>
Fig. 5.2: Label ‘Default’ is hidden after 1000 ms
Note: ‘#” is used to select the ‘id’; whereas ‘.’ is sued to access the ‘class’.
• In the below code, the label ‘Danger’ is removed; and “opacity=‘0.5’” is set for rest of the labels. Here,
‘.label’ selects all the classes which have the name ‘label’ in it. Since all the entries have classes with name
‘label’, therefore all are selected and faded according to ‘opacity=‘0.5’, as shown in Fig. 5.3.
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7
8 
11
12 </head>
13 <body>
14
18 </div>
19 </div>
20

27
28
29
30
35
37 $(function() {
39 $(".label-danger").hide(); // hide class = 'label' using . operator
40 $(".label").css({opacity:'0.5'}); // add opacity to all classes with name 'label'
41 });
42 </script>
43 </body>
44 </html>
Fig. 5.3: Faded labels
5.2.2 jQuery in separate file
It is better to write the jQuery in the separate files, therefore the codes are more manageable.
• For this, first write the code in the separate file ‘my_jquery.js’ as below,
Note: ‘html’ is used to change the content of the ‘id’ as shown in Line 5 below listing (see Fig. 5.4)
1 // asset/js/my_jquery.js
2
3 $(function() {
5 $(".label-danger").html("Shark is dangerous"); // change content using 'html'
6 });
• Next, import this file to ‘html’ as shown in Line 35 of below code,
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7
8 
11
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Chapter 5. jQuery
12 </head>
13 <body>
14
18 </div>
19 </div>
20
27
28
29
30
35 <script src="asset/js/my_jquery.js"></script>
36
37 </body>
38 </html>
Fig. 5.4: Changed content using ‘html’ option
5.2.3 Get input from user
Below is the complete html code, which we will use in this section,
Listing 5.1: complete HTML code
2
3 <!DOCTYPE html>
4 <html>
5 <head>
7
8 
11
12 </head>
13 <body>
14
18 </div>
19 </div>

20
27
28 <br><br>
29 <span class="btn btn-sm btn-warning" id="b_warning">Toggle Warning Label</span>
30
31 <br><br>
32 
33 <span class="btn btn-sm btn-default label-btn" label_id='l_default'>Toggle Default Label</span>
34 <span class="btn btn-sm btn-primary label-btn" label_id='l_primary'>Toggle Primary Label</span>
35 <span class="btn btn-sm btn-success label-btn" label_id='l_success'>Toggle Success Label</span>
36 <span class="btn btn-sm btn-info label-btn" label_id='l_info'>Toggle Info Label</span>
37 <span class="btn btn-sm btn-warning label-btn" label_id='l_warning'>Toggle Warning Label</span>
38 <span class="btn btn-sm btn-danger label-btn" label_id='l_danger'>Toggle Danger Label</span>
39
40
45 <script src="asset/js/my_jquery.js"></script>
46
47 </body>
48 </html>
5.2.3.1 Toggle label on mouse click
In this section, the ‘mouse click’ on the button ‘Toggle Warning Label (Line 29)’ is read; and then the label
‘warning’ is toggled.
• The method ‘on’ waits for user’s input ‘click (i.e. mouse click)’.
• On mouse-click next query i.e. ‘toggle’ is executed which hides/unhide the ‘warning label’ as shown in Fig.
5.5 - Fig. 5.6.
2
3 // 'hide label' and 'change content'
4 $(function() {
7 });
8
9
10 // toggle 'warning label' based on click on the button 'Toggle Warning Label'
11 $(function() {
12 $('#b_warning').on('click', function(){
13 $('#l_warning').toggle();
14 });
15 });
5.2.3.2 Toggle label based on the buttons
In previous section, we wrote the code which can toggle only one label. In this section, we will toggle multiple
labels by writing one-generalized-jQuery as shown in Fig. 5.7.
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Fig. 5.5: Hide label ‘warning’
Fig. 5.6: Show label ‘warning’
• Lines 21-26 and 31-38 of Listing 5.1 are used for this section,
• Custom attributes “label_id=. . . ” are added in each button which has the value which corresponds to one
of the ‘label’s id’. e.g. ‘label_id’ for Line 33 (i.e. l_default) is same as ‘id’ at Line 21.
• Next, in the below jQuery, we saved the ‘label_id’ in a variable (see Line 21) and then the variable is used
to toggle the labels.
Listing 5.2: Toggle the label based on the button-clicked
2
3 // 'hide label' and 'change content'
4 $(function() {
7 });
8
9
10 // toggle 'warning label' based on click on the button 'Toggle Warning Label'
11 $(function() {
12 $('#b_warning').on('click', function(){
13 $('#l_warning').toggle();
14 });
15 });
16
17
18 // toggle panels according to the clicked-buttons
19 $(function(){
20 $('.label-btn').on('click', function(){ // select class 'label-btn'
21 var labelId = $(this).attr('label_id'); // store the attribute value of 'label_id'
Fig. 5.7: Toggle labels based on button-clicked

5.3. Selectors
22 $('#' + labelId).toggle(); // toggle the label with id stored in 'label_id'
23 });
24 });
5.3 Selectors
In this section, we will use following HTML to understand the various combination of the selectors which are
summarized in Table 5.1,
<!DOCTYPE html>
<html>
<head>
<title>jQuery Selectors</title>
</head>
<body>
<p>jQuery Selectors</p>
<p class="foo"> Paragraph with class.</p>
<p><span>Paragraph with span.</span></p>
<p id="bar">Paragraph with ID. <span class="foo">Span with class and inside the paragraph-with-id.</
˓→span></p>
<div>
<p my-id="my_para">Paragraph (with custom id) inside the div</p>
<p my-id="my_para2"><span>Span inside the paragraph (with custom id) inside the div</span></p>
</div>

<script src="asset/js/jquery-3.3.1.min.js"></script>
</body>
</html>
Note:
• Press ‘ctrl+shift+k’ (or go to Tools->Web Developer->Web Console) to open the web-console in Firefox
and click on ‘console’ and type the ‘jQuery’ commands there.
• Press ‘ctrl+shift+J’ (or go to Tools->Javascript Console) in ‘Chrome’ and type the jQuery commands there.
• In this tutorial, the output of the ‘Firefox’ are shown.
5.3.1 Select elements
5.3.1.1 Select HTML elements
HTML elements, e.g. div, p, span and table etc., can be selected by writing them with the quotation mark as
shown in below codes.
• Here, ‘$(‘p’) is the command, whereas the lines below it are the outputs.
• The outputs show the ‘selected elements’; and the total number of selected elements i.e. ‘length: 6’.
• If we put the cursor to one of the outputs, then it will highlight the corresponding elements in the html as
shown in Fig. 5.8.
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Chapter 5. jQuery
$('p')
{...}
0: <p>
1: <p class="foo">
2: <p>
3: <p id="bar">
4: <p my-id="my_para">
5: <p my-id="my_para2">
length: 6
Fig. 5.8: Output of $(‘p’); (see red-squares)
• Similarly, we can select ‘div’ elements
$('div')
{...}
0: <div>
length: 1
5.3.1.2 Select class
Class can be selected using ‘.’ operator. In below code, class ‘foo’ is selected.
$(".foo")
{...}
0: <p class="foo">
1: <span class="foo">
length: 2
5.3.1.3 Select ID
ID can be selected using ‘#’ operator. In the below code, id ‘bar’ is selected.
$('#bar')
[...]
0: <p id="bar">
length: 1
5.3.1.4 Combining selectors
We can select a element with speciﬁc class name using ‘.’ operator as shown in below code. Here element ‘span’
with class ‘foo’ is selected,

5.3. Selectors
$("span.foo")
{...}
length: 1
5.3.1.5 Multiple selectors
Use ‘,’ to select diﬀerent types of elements. In the below code, “paragraph with id ‘bar’” and “elements with class
‘foo’” are selected ,
$('p#bar, .foo')
{...}
0: <p class="foo">
1: <p id="bar">
length: 3
5.3.1.6 Select descendant element
Select ‘span’ inside the ‘p’ (use space between ‘span’ and ‘p’),
$('p span')
{...}
0: <span>
2: <span>
length: 3
5.3.1.7 Select child element
The ‘>’ is used to select the child of an element.
$('div>span')
{...}
length: 0
Note: There is one element inside ‘div’ but it’s path is ‘div->p->span’ therefore ‘span’ is a child of ‘p’ (not of
‘div’). But tgis ‘span’ is the descendant of ‘div’ therefore can be accessed using space,
$('div span')
{...}
0: <span>
length: 1
5.3.1.8 Attribute selector
Custom attributes can be selected as below,
$('[my-id = my_para]')
{...}
length: 1
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Chapter 5. jQuery
$('p[my-id != my_para]') // select p with 'my-id != my_para'
{...}
0: <p>
1: <p class="foo">
2: <p>
3: <p id="bar">
length: 5
$('p[class = foo]')
{...}
0: <p class="foo">
length: 1
5.3.2 Filters
Various filter options (e.g. filter, first, last and has etc.) can be used after ‘:’ as shown below,
$('p:first') // select first element
{...}
0: p
$('p:last') // last element
{...}
length: 1
$('p:not(.foo)') // 'p' which does not have class 'foo'
{...}
0: <p>
1: <p>
2: <p id="bar">
length: 5
$('p:has(span)') // 'p' which has 'span' inside it
{...}
0: <p>
1: <p id="bar">
length: 3
$('p:hidden') // hidden 'p'
{...}
length: 0
$('p:visible') // visible 'p'
{...}
0: <p>
1: <p class="foo">
2: <p>
3: <p id="bar">
length: 6
$('p:contains(with class)') // paragraph which contains class inside it

5.3. Selectors
{...}
0: <p class="foo">
1: <p id="bar">
length: 2
$('p').filter(".foo") // same as p.foo
{...}
0: <p class="foo">
length: 1
$('p').not(".foo") // p with not class foo
{...}
0: <p>
1: <p>
2: <p id="bar">
length: 5
$('p').last() // last element of 'p'
{...}
length: 1
$('p').has('span') // p with span
{...}
0: <p>
1: <p id="bar">
length: 3
$('p').is('.foo') // does 'p' contain 'foo'
true
$('p').children() // children of 'p'
{...}
0: <span>
2: <span>
length: 3
$('p').children(".foo") // child of 'p' with class 'foo'
{...}
length: 1
Table 5.1: Selectors
Command Description example
$(‘elementName’) select the tags (p, body, table) $(‘p’), $(‘body’)
$(‘.className’) select element with ‘className’ $(“.foo”)
$(‘elementName.className’) element with className $(“span.foo”)
$(selector1, selector2) select selector1 and selector2 $(‘p#bar, .foo’)
$(selector1 selector2) select selector2 inside selector1 $(‘p span’)
$(selector1>selector2) select selector2 which is child of selector1 $(‘div>span’)
$(attributName = someName) select attribute with someName $(‘[my-id = my_para]’)
$p(attributName = someName) select ‘p’ with attribute with someName $(‘p[my-id = my_para]’)
See Section 5.3.2 for ﬁlters
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Chapter 5. jQuery
5.4 Operations
In Listing 5.2 we saw some operations e.g. ‘hide()’ and ‘toggle()’. Table 5.2 shows some more such operations.
Table 5.2: Operations
Operations
hide() hide(speed) fadeIn(speed) fadeOut(speed)
show() show(speed) slideDown(speed) slideToggle(speed)
slideUp(speed) toggle() toggle(speed) toggle(switch)
5.5 Event handling
In Listing 5.2 we saw one example of event handling, where certain operations are performed on the event ‘mouse
click’. Table 5.2 shows a list of some more events.
Table 5.3: Event handle
Events
click keydown keypress keyup
mousedown mouseover

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