10 Selenium JavaScript Interview Questions and Answers

Selenium JavaScript is a powerful tool for automating web applications for testing purposes. It allows developers to write scripts in JavaScript to control browser actions, making it an essential skill for ensuring the quality and functionality of web applications. Selenium’s compatibility with various browsers and its ability to integrate with other testing frameworks make it a versatile choice for developers and QA engineers alike.

This article provides a curated selection of interview questions and answers focused on Selenium JavaScript. By familiarizing yourself with these questions, you can gain a deeper understanding of the tool’s capabilities and be better prepared to demonstrate your expertise in a technical interview setting.

Selenium JavaScript Interview Questions and Answers

1. How would you locate an element by its ID and click on it?

To locate an element by its ID and click on it using Selenium in JavaScript, use the findElement method with the By.id locator. This method efficiently interacts with web elements using the ID attribute.

Example:

const { Builder, By } = require('selenium-webdriver');

(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://www.example.com');
        let element = await driver.findElement(By.id('elementID'));
        await element.click();
    } finally {
        await driver.quit();
    }
})();

2. Write a script to fill out a form and submit it.

To fill out a form and submit it using Selenium with JavaScript, follow these steps:

1. Set up Selenium WebDriver.
2. Locate the form elements.
3. Interact with the elements to fill them out.
4. Submit the form.

Example:

const { Builder, By } = require('selenium-webdriver');

(async function fillForm() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://example.com/form');

        await driver.findElement(By.name('username')).sendKeys('testuser');
        await driver.findElement(By.name('password')).sendKeys('password123');
        await driver.findElement(By.name('email')).sendKeys('[email protected]');

        await driver.findElement(By.css('form')).submit();
    } finally {
        await driver.quit();
    }
})();

3. How do you implement explicit waits in your script?

Explicit waits in Selenium allow you to wait for a specific condition before proceeding. This is done using the WebDriverWait class with the until method, which specifies the condition to be met.

Example:

const { Builder, By, until } = require('selenium-webdriver');

(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://www.example.com');
        let element = await driver.wait(until.elementLocated(By.id('some-id')), 10000);
        await element.click();
    } finally {
        await driver.quit();
    }
})();

4. Write a script to drag and drop an element from one location to another.

To perform a drag-and-drop operation using Selenium with JavaScript, utilize the Actions class. This class allows you to build complex user interactions.

Example:

const { Builder, By } = require('selenium-webdriver');
const { Actions } = require('selenium-webdriver/lib/actions');

(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://example.com/drag_and_drop');

        let sourceElement = await driver.findElement(By.id('source'));
        let targetElement = await driver.findElement(By.id('target'));

        let actions = new Actions(driver);
        await actions.dragAndDrop(sourceElement, targetElement).perform();
    } finally {
        await driver.quit();
    }
})();

5. How can you execute JavaScript code within your Selenium script?

In Selenium, executing JavaScript code within your script can be useful for interacting with elements not easily accessible through standard methods. Use the executeScript method to run JavaScript in the context of the current frame or window.

Example:

const { Builder } = require('selenium-webdriver');

(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://www.example.com');
        
        let title = await driver.executeScript('return document.title');
        console.log('Page title is: ' + title);
        
        await driver.executeScript('window.scrollTo(0, document.body.scrollHeight)');
    } finally {
        await driver.quit();
    }
})();

6. Write a custom wait condition to wait for an element to be clickable.

Custom wait conditions in Selenium define specific conditions under which the WebDriver should wait. This is useful for handling dynamic web pages where elements may not be immediately available.

Example of a custom wait condition for an element to be clickable:

const { Builder, By } = require('selenium-webdriver');

async function customWaitForElementToBeClickable(driver, locator) {
    await driver.wait(async function() {
        const element = await driver.findElement(locator);
        return element.isDisplayed() && element.isEnabled();
    }, 10000, 'Element is not clickable');
}

(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://example.com');
        const locator = By.id('clickableElement');
        await customWaitForElementToBeClickable(driver, locator);
        await driver.findElement(locator).click();
    } finally {
        await driver.quit();
    }
})();

7. Write a script to handle alerts and pop-ups.

Handling alerts and pop-ups in Selenium involves using the WebDriver’s methods to switch to the alert and perform actions like accepting or dismissing it.

Example:

const { Builder, By, until } = require('selenium-webdriver');

(async function handleAlert() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://example.com');
        
        await driver.findElement(By.id('trigger-alert')).click();
        
        let alert = await driver.wait(until.alertIsPresent());
        
        let alertText = await alert.getText();
        console.log(alertText);
        
        await alert.accept();
        
    } finally {
        await driver.quit();
    }
})();

8. Write a script to take a screenshot of the current browser window.

To take a screenshot of the current browser window using Selenium with JavaScript, use the takeScreenshot method. This captures the screenshot and returns it as a base64-encoded string.

Example:

const { Builder } = require('selenium-webdriver');
const fs = require('fs');

(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://www.example.com');
        let screenshot = await driver.takeScreenshot();
        fs.writeFileSync('screenshot.png', screenshot, 'base64');
    } finally {
        await driver.quit();
    }
})();

9. Write a script to switch to an iFrame and interact with an element inside it.

To switch to an iFrame and interact with an element inside it using Selenium in JavaScript, use the switchTo method to change the context to the iFrame.

Example:

const { Builder, By } = require('selenium-webdriver');

(async function example() {
    let driver = await new Builder().forBrowser('firefox').build();
    try {
        await driver.get('http://example.com');
        
        await driver.switchTo().frame(driver.findElement(By.id('iframeID')));
        
        let element = await driver.findElement(By.id('elementID'));
        await element.click();
        
    } finally {
        await driver.quit();
    }
})();

10. Write a script to upload a file using Selenium.

To upload a file using Selenium with JavaScript, interact with the file input element on the web page. Send the file path directly to the input element.

Example:

const { Builder, By } = require('selenium-webdriver');
const path = require('path');

(async function uploadFile() {
    let driver = await new Builder().forBrowser('chrome').build();
    try {
        await driver.get('http://example.com/upload');
        
        let fileInput = await driver.findElement(By.css('input[type="file"]'));
        
        let filePath = path.resolve(__dirname, 'path/to/your/file.txt');
        
        await fileInput.sendKeys(filePath);
        
        await driver.findElement(By.css('button[type="submit"]')).click();
    } finally {
        await driver.quit();
    }
})();