Executing JavaScript in Selenium Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to execute JavaScript that returns the page title.

Selenium Java

JavascriptExecutor js = (JavascriptExecutor) driver;
String title = (String) js.executeScript([1]);

Drag options to blanks, or click blank then click option'

A"return document.title;"

B"document.title;"

C"return window.title;"

D"window.document.title"

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting 'return' causes the JavaScript to not return the title.

Using 'window.title' instead of 'document.title' is incorrect.

The JavaScript code must return the document title explicitly using 'return document.title;'.

2fill in blank

medium

Complete the code to scroll the page down by 500 pixels using JavaScript.

Selenium Java

JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript([1]);

Drag options to blanks, or click blank then click option'

A"window.scrollBy(0, 500);"

B"scrollTo(0, 500);"

C"window.scrollTo(500, 0);"

D"scrollBy(500, 0);"

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping x and y values causes horizontal instead of vertical scroll.

Using 'scrollTo' without 'window.' may cause errors.

The correct JavaScript to scroll down vertically by 500 pixels is 'window.scrollBy(0, 500);'.

3fill in blank

hard

Fix the error in the code to click an element using JavaScript.

Selenium Java

WebElement element = driver.findElement(By.id("submitBtn"));
JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript([1], element);

Drag options to blanks, or click blank then click option'

A"click(arguments[0]);"

B"element.click();"

C"arguments[0].click();"

D"arguments.click();"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'element.click()' inside the script string causes JavaScript errors.

Incorrect use of 'arguments' object leads to runtime errors.

To click an element via JavaScript, use 'arguments[0].click();' passing the element as argument.

4fill in blank

hard

Fill both blanks to return the inner text of an element found by CSS selector.

Selenium Java

JavascriptExecutor js = (JavascriptExecutor) driver;
String text = (String) js.executeScript("return document.querySelector([1]).[2];");

Drag options to blanks, or click blank then click option'

A"#main-content"

B"innerText"

C"textContent"

D".content"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a class selector without quotes causes syntax errors.

Using 'textContent' instead of 'innerText' changes the returned text.

Use a CSS selector string like '#main-content' and property 'innerText' to get visible text.

5fill in blank

hard

Fill all three blanks to create a map of element IDs to their text content for elements with class 'item'.

Selenium Java

JavascriptExecutor js = (JavascriptExecutor) driver;
Map<String, String> texts = (Map<String, String>) js.executeScript(
  "const elements = document.querySelectorAll([1]);"
  + "const result = {};"
  + "elements.forEach(el => { result[el.[2]] = el.[3]; });"
  + "return result;"
);

Drag options to blanks, or click blank then click option'

A".item"

B"id"

C"textContent"

D"className"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'className' instead of 'id' as key causes incorrect mapping.

Selecting elements without quotes causes JavaScript errors.

Select elements by '.item', use 'id' as key and 'textContent' as value in the map.

Practice

1. What is the main purpose of using JavascriptExecutor in Selenium Java?

easy

A. To locate elements on the page using JavaScript selectors

B. To execute JavaScript code directly in the browser during a test

C. To start the Selenium WebDriver session

D. To generate test reports automatically

Solution

1. Step 1: Understand the role of JavascriptExecutor

   JavascriptExecutor allows running JavaScript code inside the browser from Selenium tests.

2. Step 2: Identify the main use case

   It is mainly used to perform actions or retrieve information that Selenium WebDriver cannot do directly.

3. Final Answer:

   To execute JavaScript code directly in the browser during a test -> Option B

4. Quick Check:

   JavascriptExecutor runs JS code in browser [OK]

Hint: Remember: JavascriptExecutor runs JS code inside browser [OK]

Common Mistakes:

• Confusing JavascriptExecutor with element locators
• Thinking it starts WebDriver sessions
• Assuming it generates reports

2. Which of the following is the correct way to cast a WebDriver instance to JavascriptExecutor in Selenium Java?

easy

A. JavascriptExecutor js = driver.executeScript();

B. JavascriptExecutor js = driver.getJavascriptExecutor();

C. JavascriptExecutor js = new JavascriptExecutor(driver);

D. JavascriptExecutor js = (JavascriptExecutor) driver;

Solution

1. Step 1: Recall the casting syntax in Java

   To use JavascriptExecutor, you cast the WebDriver instance like this: (JavascriptExecutor) driver.

2. Step 2: Check each option

   JavascriptExecutor js = (JavascriptExecutor) driver; uses correct casting syntax. The other options are invalid method calls or constructors.

3. Final Answer:

   JavascriptExecutor js = (JavascriptExecutor) driver; -> Option D

4. Quick Check:

   Cast driver to JavascriptExecutor using (JavascriptExecutor) [OK]

Hint: Casting uses (JavascriptExecutor) before driver [OK]

Common Mistakes:

• Using non-existent methods like getJavascriptExecutor()
• Trying to instantiate JavascriptExecutor with new keyword
• Calling executeScript() without casting

3. What will be the output of the following code snippet?

JavascriptExecutor js = (JavascriptExecutor) driver;
String title = (String) js.executeScript("return document.title;");
System.out.println(title);

medium

A. Prints the current page's title

B. Throws a ClassCastException

C. Prints 'undefined'

D. Prints the URL of the page

Solution

1. Step 1: Understand the JavaScript executed

   The script returns document.title, which is the page's title as a string.

2. Step 2: Check the casting and output

   The returned object is cast to String and printed, so it outputs the page title.

3. Final Answer:

   Prints the current page's title -> Option A

4. Quick Check:

   executeScript returns document.title string [OK]

Hint: executeScript returns JS value; cast to String for title [OK]

Common Mistakes:

• Expecting URL instead of title
• Not casting return value to String
• Confusing output with undefined or errors

4. Identify the error in the following code snippet:

JavascriptExecutor js = (JavascriptExecutor) driver;
js.executeScript("arguments[0].click();");

medium

A. Incorrect casting of driver to JavascriptExecutor

B. executeScript method does not exist

C. Missing WebElement argument to click()

D. JavaScript syntax error in the string

Solution

1. Step 1: Analyze the executeScript call

   The script uses arguments[0].click(); which requires a WebElement passed as an argument.

2. Step 2: Check the method call parameters

   No WebElement is passed to executeScript, so it will fail at runtime.

3. Final Answer:

   Missing WebElement argument to click() -> Option C

4. Quick Check:

   arguments[0] needs a WebElement passed [OK]

Hint: Pass WebElement as argument when using arguments[0] [OK]

Common Mistakes:

• Forgetting to pass WebElement argument
• Assuming casting is wrong
• Thinking executeScript method is missing

5. You want to scroll a page to a specific WebElement using JavaScript in Selenium Java. Which code snippet correctly achieves this?

hard

A. js.executeScript("arguments[0].scrollIntoView(true);", element);

B. js.executeScript("window.scrollTo(element);");

C. js.executeScript("scrollToElement(arguments[0]);", element);

D. js.executeScript("document.scrollTo(arguments[0]);");

Solution

1. Step 1: Recall JavaScript method to scroll to element

   The correct JS method is scrollIntoView(true) called on the element.

2. Step 2: Check the Selenium executeScript usage

   Pass the WebElement as an argument and use arguments[0].scrollIntoView(true); to scroll.

3. Final Answer:

   js.executeScript("arguments[0].scrollIntoView(true);", element); -> Option A

4. Quick Check:

   Use scrollIntoView with element argument [OK]

Hint: Use arguments[0].scrollIntoView(true) with element [OK]

Common Mistakes:

• Using window.scrollTo with element (invalid)
• Calling non-existent scrollToElement function
• Not passing element as argument