DevTestOps Insights by Pankaj

JavaScriptExecutor in Selenium with Examples

Pankaj Suryavanshi's photo
Pankaj Suryavanshi
·

3 min read

Table of contents

Introduction

Selenium is a powerful tool for automated testing of web applications, but there are scenarios where interacting with the browser using traditional Selenium commands may not be sufficient. This is where JavaScriptExecutor comes into play. In this blog, we'll explore what JavaScriptExecutor is and how it can be utilized in Selenium with Java.

What is JavaScriptExecutor?

JavaScriptExecutor is an interface provided by Selenium WebDriver to execute JavaScript code within the context of the currently selected window or frame. JavaScript is a scripting language that interacts with HTML and enhances the capabilities of Selenium by allowing you to perform actions that are not directly supported by WebDriver commands.

Methods provided by JavaScriptExecutor

1. executeScript

This method executes JavaScript in the currently selected window or frame. The script runs as an anonymous function, and it can return various data types such as WebElement, List, String, Long, or Boolean.

// Import the package
import org.openqa.selenium.JavascriptExecutor;

// Create a reference
JavascriptExecutor js = (JavascriptExecutor) driver;

// Execute the script
js.executeScript(script, args);

2. executeAsyncScript

This method is used to execute asynchronous JavaScript in the current window or frame. Asynchronous JavaScript executes in a single thread while the rest of the page continues parsing, enhancing performance.

Getting Started with JavaScriptExecutor

To use JavaScriptExecutor in Selenium:

  1. Import the package:
import org.openqa.selenium.JavascriptExecutor;
  1. Create a reference:
JavascriptExecutor js = (JavascriptExecutor) driver;
  1. Call the JavaScriptExecutor method:
js.executeScript(script, args);

Examples of JavaScriptExecutor in Selenium

Example 1: Refresh the browser window

JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript("location.reload()");

Example 2: Send text to an element

JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript("document.getElementById('elementId').value = 'xyz';");

Example 3: Generate an Alert Pop Window

JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript("alert('hello world');");

Example 4: Get InnerText of a Webpage

JavascriptExecutor js = (JavascriptExecutor) driver;
String sText = (String) js.executeScript("return document.documentElement.innerText;");

Example 5: Get Title of a WebPage

JavascriptExecutor js = (JavascriptExecutor) driver;
String sText = (String) js.executeScript("return document.title;");

Example 6: Scroll Page

JavascriptExecutor js = (JavascriptExecutor) driver;
// Vertical scroll – down by 150 pixels
js.executeScript("window.scrollBy(0,150)");

Best Practices for Using JavaScriptExecutor

  1. Avoid Using Hard Waits: JavaScriptExecutor can execute asynchronously, so prefer using it along with WebDriver's wait mechanism to ensure synchronization.

  2. Error Handling: Wrap your JavaScriptExecutor calls in try-catch blocks to handle any potential exceptions gracefully.

  3. Document Your Scripts: Clearly document the purpose and functionality of your JavaScriptExecutor scripts for better code maintainability.

  4. Testing in Multiple Browsers: Test your JavaScriptExecutor scripts across different browsers to ensure cross-browser compatibility.

Conclusion

JavaScriptExecutor in Selenium provides a powerful way to interact with web elements using JavaScript, giving testers more flexibility and control over their automated tests. Utilizing JavaScriptExecutor, you can perform actions and retrieve information that may not be possible with traditional Selenium WebDriver commands.

By following best practices and understanding the nuances of JavaScriptExecutor, you can enhance the robustness and reliability of your Selenium test scripts. As you explore and incorporate JavaScriptExecutor into your testing strategy, you'll find that it opens up a world of possibilities for automating complex scenarios in web applications.

seleniumselenium-webdriverJavaJavaScript