Java script Tutorial - QaTrainingHub

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JAVASCRIPT
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Software Training InstituteSoftware Training Institute

INTRODUCTION TO JAVASCRIPTINTRODUCTION TO JAVASCRIPT
Introduction:
JS is client side scripting language implemented by
Brendan Netscape corporation in 1995 as LiveScript.
It increase the performance of application and to
decrease network traffic. JavaScript is the most
popular scripting language on the internet, and works
in all major browsers, such as Internet Explorer,
Firefox, Chrome, Opera, and Safari.

•JavaScript was designed to add interactivity to HTML pages
•JavaScript was originally developed in Netscape, by Brendan Eich
•JavaScript is a scripting language
•A scripting language is a lightweight programming language
•JavaScript is usually embedded directly into HTML pages
•Every Statement is JS we should end with a semi colon ;
•JavaScript is an interpreted language (means that scripts execute
without preliminary compilation)
•Everyone can use JavaScript without purchasing a license
• JavaScript is loosely typed language, no need to provide data
types at the time of variable declaration.
• User can see the JavaScript logic by clicking on view source
option.
What is JavaScript?

NO!
JAVA and JavaScript are two completely different languages
in both concept and design!
Java (developed by Sun Microsystems) is a powerful and
much more complex programming language - in the same
category as C and C++.
Are Java and JavaScript the same?

HOW JAVASCRIPT WORKS
HTML Viewer Executing Scripts

Java Script Structure
<html><html>
<head><head>
<title>example</title><title>example</title>
<script language=“JavaScript”><script language=“JavaScript”>
<!–<!–
----->----->
</script></script>
</head></head>
<body><body>
----------
----------
</body></body>
</html></html> QATRAININGHUB.COM | India's BestQATRAININGHUB.COM | India's Best

COMMENTS
Single Comments are //Single Comments are //
<script type="text/javascript"><script type="text/javascript">
document.write("Hello"); // This will write "Hello"document.write("Hello"); // This will write "Hello"
document.write("Dolly"); // This will write "Dolly"document.write("Dolly"); // This will write "Dolly"
</script></script>
Multi line comments are /* */Multi line comments are /* */
<script type="text/javascript"><script type="text/javascript">
/*/*
document.write("<h1>This is a header</h1>"); document.write("<p>This isdocument.write("<h1>This is a header</h1>"); document.write("<p>This is
a paragraph</p>");a paragraph</p>");
document.write("<p>This is also paragraph</p>");document.write("<p>This is also paragraph</p>");
*/*/
</script></script> QATRAININGHUB.COM | India's BestQATRAININGHUB.COM | India's Best

Comparing Java and JavaScript

Debugging JavaScript Errors
Enable JavaScript - Internet Explorer
1.Click on the Tools menu
2.Choose Internet Options... from the menu
3.Click the Security tab on the Internet Options pop up
4.Click the Custom Level... button to access your security settings
5.Scroll almost all the way down to the Scripting section
6.Select the Enable button for Active scripting
7.Click OK to finish the process 8.Click Yes when asked to confirm

Enable JavaScript – Firefox
2.Choose Options... from the menu
3.Click the Content tab in the Options pop up
4.Make sure that Enable JavaScript is checked
5.Click OK to finish the process

Enable JavaScript – Opera
2.Choose Preferences... from the menu
3.Click the Advanced tab in the Preferences pop up
4.Select Content from the list of items on the left
5.Make sure that Enable JavaScript is checked
6.Click OK to finish the process

COMMON SCRIPTING TASKSCOMMON SCRIPTING TASKS
Adding dynamic features to Web pagesAdding dynamic features to Web pages
Validation of form dataValidation of form data
Image rolloversImage rollovers
Time-sensitive or random page elementsTime-sensitive or random page elements
Handling cookiesHandling cookies

LIMITATIONS OF CLIENT-SIDE SCRIPTING
Since script code is embedded in the page, viewable to the worldSince script code is embedded in the page, viewable to the world
for security reasons, scripts are limited in what they can dofor security reasons, scripts are limited in what they can do
Example: Can't access the client's hard driveExample: Can't access the client's hard drive
since designed to run on any machine platform, scripts do not containsince designed to run on any machine platform, scripts do not contain
platform specific commandsplatform specific commands
script languages are not full-featuredscript languages are not full-featured
e.g., JavaScript objects are crude, not good for large projecte.g., JavaScript objects are crude, not good for large project
developmentdevelopment

Introducing JavaScript
Server-Side
Programming
Client-Side
Programming

Java script Tutorial - QaTrainingHub

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