JavaScript executor basics in Selenium Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this JavaScript executor call in Selenium?

Consider the following Python Selenium code snippet that uses JavaScript executor to get the page title. What will be printed?

Selenium Python

title = driver.execute_script('return document.title;')
print(title)

A Prints the entire HTML content of the page

B Prints None because execute_script returns nothing

C Raises a SyntaxError in Python

D Prints the current page title as a string

💡 Hint

Remember that execute_script can return values from JavaScript to Python.

The JavaScript code 'return document.title;' returns the page title string to Python, so the variable 'title' holds that string and prints it.

❓ assertion

intermediate

Which assertion correctly verifies the page background color using JavaScript executor?

You want to check if the page background color is exactly 'rgb(255, 255, 255)'. Which Python assertion with JavaScript executor is correct?

Selenium Python

color = driver.execute_script('return window.getComputedStyle(document.body).backgroundColor;')

A assert color != 'rgb(255, 255, 255)'

B assert color == 'rgb(255, 255, 255)'

C assert color = 'rgb(255, 255, 255)'

D assert color is 'rgb(255, 255, 255)'

💡 Hint

Use the equality operator '==' for value comparison in assertions.

Option B uses the correct equality operator '==' to compare the string values. Option B uses assignment '=' which is invalid in assert. Option B asserts the opposite. Option B uses 'is' which checks identity, not value equality.

❓ locator

advanced

Which JavaScript executor code correctly scrolls to an element by its ID?

You want to scroll the page to an element with id 'footer' using JavaScript executor in Selenium Python. Which code snippet is correct?

A driver.execute_script('document.getElementById("footer").scrollIntoView();')

B driver.execute_script('document.querySelector("#footer").scrollTo();')

C driver.execute_script('document.getElementById("footer").scrollToView();')

D driver.execute_script('document.querySelector("footer").scrollIntoView();')

💡 Hint

Use the correct JavaScript method to scroll an element into view.

Option A correctly uses getElementById and scrollIntoView(). Option A uses scrollTo() which is not a method of elements. Option A uses a non-existent method scrollToView(). Option A uses querySelector with 'footer' which selects elements by tag name, not id.

🔧 Debug

advanced

Why does this JavaScript executor call raise an error?

This Python Selenium code raises an error. Identify the cause.

Selenium Python

driver.execute_script('return document.querySelectorAll(".btn").forEach(el => el.click())')

A Python cannot execute JavaScript with arrow functions

B Syntax error in the JavaScript arrow function

C forEach returns undefined, so returning it causes an error

D document.querySelectorAll does not exist

💡 Hint

Check what the forEach method returns in JavaScript.

The forEach method returns undefined in JavaScript. Returning undefined from execute_script is allowed but if Python expects a value, it may cause issues. The error is likely due to returning undefined. The arrow function syntax is correct, and querySelectorAll exists. Python can execute any JavaScript string.

❓ framework

expert

In Selenium Python, which approach correctly waits for an element to be clickable before clicking it using JavaScript executor?

You want to wait until an element with id 'submit' is clickable, then click it using JavaScript executor. Which code snippet correctly implements this?

Selenium Python

from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

wait = WebDriverWait(driver, 10)

A

wait.until(EC.element_to_be_clickable((By.ID, 'submit')))
driver.execute_script('document.getElementById("submit").click();')

B

driver.execute_script('document.getElementById("submit").click();')
wait.until(EC.element_to_be_clickable((By.ID, 'submit')))

C

wait.until(EC.presence_of_element_located((By.ID, 'submit')))
driver.execute_script('document.getElementById("submit").click();')

D

wait.until(EC.visibility_of_element_located((By.ID, 'submit')))
driver.execute_script('document.getElementById("submit").click();')

💡 Hint

Wait for the element to be clickable before clicking it.

Option A waits for the element to be clickable, which means visible and enabled, then clicks it via JavaScript executor. Option A clicks before waiting, which may fail. Option A waits only for presence, not clickability. Option A waits for visibility but not necessarily enabled state.