How to click the 'Ok' button inside an alert window with a Java Selenium command?

An alert window is a pop-up box shown over the webpage to convey error messages using the alert() function of JavaScript. It has only one button "OK" which the user must press to continue browsing the webpage. A person might automate the website testing process and stumble upon pages that display alert messages and have to acknowledge the alert box to continue the testing process. In this tutorial, we will be using Selenium and Java to press the OK button inside the alert window.

Before beginning we have to create a Java Project with or without build tools (Maven/Gradle) to use Selenium.

Steps to create a simple Java Project for Selenium

1. You must have a well-known IDE such as VS Code, IntelliJ, or Eclipse. In this article, we will be using VS Code. Install all the necessary Java extensions suggested by Microsoft to run Java applications and create Java projects.

2. Create and open a folder and open the command palette inside VS Code using Ctrl+Shift+P and type Java: Create a new project and provide the project name.

3. Download the latest Selenium package for Java from the official website. Extract the downloaded zip file inside /lib folder of our project.

4. Now we are ready to write code inside the /src/App.java file. Also, you must have the respective driver for your browser.

Steps to click the OK button inside the Alert window

It is important to acknowledge the presence of an alert window by pressing the OK button before trying to do any other tasks such as get page title, element, etc. otherwise we will get UnhandledAlertException. In order to press the OK button inside the alert window, we must also confirm if the alert window is actually present. Otherwise, selenium will throw NoAlertPresentException. Hence we must handle this exception using try-catch blocks.

Using switchTo().alert().accept() method

import org.openqa.selenium.NoAlertPresentException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

public class App {
    public static void main(String[] args) throws Exception {
        System.setProperty("webdriver.chrome.driver", "C:\\Drivers\\chromedriver.exe");

        WebDriver driver = new ChromeDriver();

        driver.get("https://globbertrot.github.io/alertpage");

        try {
            driver.switchTo().alert().accept();
            System.out.println(driver.getTitle());
        } catch (NoAlertPresentException e) {
            System.out.println(driver.getTitle());
        }

        driver.quit();
    }  
}

Explanation

• We are using switchTo().alert() method of the driver object which changes the context or focus of the WebDriver from entire webpage to the alert window.
• It returns an Alert object which has many methods such has accept(), dismiss() (in case of confirm box), sendKeys() (in case of prompt box).
• We can use the accept() method in order to press the OK button.
• We are also handling the NoAlertPresentException which is thrown if we are trying to access alert box which is not even present.

Output

Conclusion

Handling alert pop-ups in Selenium Java is essential for dealing with unexpected prompts during test execution. By using the Alert interface, you can easily interact with alert windows and manage actions like clicking the "Ok" button. Mastering this technique ensures that your test scripts handle unexpected pop-ups efficiently, leading to more reliable and stable automated testing.