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Selenium WebDriver Fundamentals

In short

Selenium lets your code drive a real browser: open pages, type, click and check. It has been the default first automation tool in QA for well over a decade.

The most widely used browser automation library — controlling a real browser programmatically to click, type, and verify web page behavior, the foundation of most web test automation careers.

The purple blob steers a small toy car across the floor with a remote control.

Think of it like this

The remote-control car

You press buttons on the remote, a signal goes to the receiver, and the car turns left. Your script is the remote, the browser driver is the receiver, and Chrome is the car doing exactly what you pressed.

Watch it happen

How one click travels

Test script

ChromeDriver

Browser

new session

1/6webdriver.Chrome() starts a driver process and asks it for a new browser session.

The big ideas

What you need to know

Driver in the middle

Every browser has its own driver: chromedriver, geckodriver, safaridriver. Selenium Manager downloads the right one for you.

Find, then act

Almost every step is find_element followed by click, send_keys or reading .text.

Many languages

Official bindings exist for Java, Python, C#, JavaScript and Ruby. Same ideas in each.

Always quit

driver.quit() closes the browser and the driver. Forget it and dozens of Chrome windows pile up.

See it in code

Walk through the code

python

1from selenium import webdriver2from selenium.webdriver.common.by import By3 4driver = webdriver.Chrome()  # Selenium Manager fetches the driver5driver.get("https://www.saucedemo.com/")6 7driver.find_element(By.ID, "user-name").send_keys("standard_user")8driver.find_element(By.ID, "password").send_keys("secret_sauce")9driver.find_element(By.ID, "login-button").click()10 11assert "inventory" in driver.current_url12driver.quit()

1/3Start Chrome and open the page. Since Selenium 4.6 you don't download drivers by hand.

A complete login test against Sauce Demo, a public practice site. Install with pip install selenium.

Save yourself the pain

Common mistakes

Oops

Downloading a random chromedriver.exe and fighting version mismatch errors.

Do this instead

Use Selenium 4.6 or newer and let Selenium Manager match the driver to your browser.

Oops

Writing a test with no assert, just clicks.

Do this instead

A test without a check only proves the clicks didn't crash. Always verify an outcome.

Your mission

Automate one login

~30 min

Quick check

What does ChromeDriver do in a Selenium test?

Go deeper

1Set up Selenium WebDriver and write a script that opens a browser and navigates to a page.
2Learn the basic WebDriver API: find elements, interact with them, and assert their state.
3Practice running the same script against a different browser to see cross-browser behavior.