Selenium Skill

Complete guide for Selenium - cross-browser automation.

Quick Reference

Supported Browsers

Browser	Driver
Chrome	ChromeDriver
Firefox	GeckoDriver
Safari	SafariDriver
Edge	EdgeDriver

Key Components

- WebDriver: Browser control
- WebElement: Page elements
- Wait: Synchronization
- Actions: Complex interactions

1. Installation

Python

bash

pip install selenium webdriver-manager

Java (Maven)

xml

<dependency>
    <groupId>org.seleniumhq.selenium</groupId>
    <artifactId>selenium-java</artifactId>
    <version>4.18.1</version>
</dependency>

JavaScript

bash

npm install selenium-webdriver

2. Basic Setup (Python)

Chrome

python

from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from webdriver_manager.chrome import ChromeDriverManager

# Auto-install driver
driver = webdriver.Chrome(service=Service(ChromeDriverManager().install()))

# Navigate
driver.get("https://example.com")

# Close
driver.quit()

Firefox

python

from selenium.webdriver.firefox.service import Service
from webdriver_manager.firefox import GeckoDriverManager

driver = webdriver.Firefox(service=Service(GeckoDriverManager().install()))

Options

python

from selenium.webdriver.chrome.options import Options

options = Options()
options.add_argument("--headless")
options.add_argument("--no-sandbox")
options.add_argument("--disable-dev-shm-usage")
options.add_argument("--window-size=1920,1080")
options.add_argument("--disable-gpu")
options.add_argument("user-agent=Custom User Agent")

driver = webdriver.Chrome(options=options)

3. Finding Elements

Locator Strategies

python

from selenium.webdriver.common.by import By

# By ID
element = driver.find_element(By.ID, "my-id")

# By class name
element = driver.find_element(By.CLASS_NAME, "my-class")

# By name
element = driver.find_element(By.NAME, "username")

# By tag name
element = driver.find_element(By.TAG_NAME, "input")

# By link text
element = driver.find_element(By.LINK_TEXT, "Click here")
element = driver.find_element(By.PARTIAL_LINK_TEXT, "Click")

# By CSS selector
element = driver.find_element(By.CSS_SELECTOR, "div.container > p")

# By XPath
element = driver.find_element(By.XPATH, "//button[@type='submit']")

# Find multiple elements
elements = driver.find_elements(By.CSS_SELECTOR, ".item")

XPath Examples

python

# By text content
driver.find_element(By.XPATH, "//button[text()='Submit']")

# Contains text
driver.find_element(By.XPATH, "//div[contains(text(), 'Hello')]")

# By attribute
driver.find_element(By.XPATH, "//input[@placeholder='Search']")

# Parent/child
driver.find_element(By.XPATH, "//div[@class='parent']//span")

# Following sibling
driver.find_element(By.XPATH, "//label[text()='Email']/following-sibling::input")

# Index
driver.find_element(By.XPATH, "(//div[@class='item'])[1]")

4. Interactions

Basic Actions

python

# Click
element.click()

# Type text
element.send_keys("Hello World")

# Clear input
element.clear()

# Submit form
element.submit()

# Get text
text = element.text

# Get attribute
value = element.get_attribute("href")
class_name = element.get_attribute("class")

# Check state
is_displayed = element.is_displayed()
is_enabled = element.is_enabled()
is_selected = element.is_selected()

Keyboard Actions

python

from selenium.webdriver.common.keys import Keys

# Special keys
element.send_keys(Keys.ENTER)
element.send_keys(Keys.TAB)
element.send_keys(Keys.ESCAPE)

# Key combinations
element.send_keys(Keys.CONTROL + "a")
element.send_keys(Keys.CONTROL + "c")

# Clear and type
element.send_keys(Keys.CONTROL + "a")
element.send_keys("new text")

Select Dropdowns

python

from selenium.webdriver.support.ui import Select

select = Select(driver.find_element(By.ID, "dropdown"))

# By visible text
select.select_by_visible_text("Option 1")

# By value attribute
select.select_by_value("opt1")

# By index
select.select_by_index(0)

# Get selected option
selected = select.first_selected_option.text

# Get all options
options = select.options
for option in options:
    print(option.text)

5. Waits

Implicit Wait

python

# Apply to all find_element calls
driver.implicitly_wait(10)  # seconds

Explicit Wait

python

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

wait = WebDriverWait(driver, 10)

# Wait for element present
element = wait.until(
    EC.presence_of_element_located((By.ID, "my-id"))
)

# Wait for element visible
element = wait.until(
    EC.visibility_of_element_located((By.CSS_SELECTOR, ".visible"))
)

# Wait for element clickable
element = wait.until(
    EC.element_to_be_clickable((By.XPATH, "//button"))
)

# Wait for text
wait.until(
    EC.text_to_be_present_in_element((By.ID, "status"), "Complete")
)

# Wait for URL
wait.until(EC.url_contains("dashboard"))
wait.until(EC.url_to_be("https://example.com/dashboard"))

# Wait for title
wait.until(EC.title_contains("Dashboard"))

Common Expected Conditions

python

EC.presence_of_element_located()
EC.visibility_of_element_located()
EC.element_to_be_clickable()
EC.invisibility_of_element_located()
EC.staleness_of()
EC.frame_to_be_available_and_switch_to_it()
EC.alert_is_present()
EC.number_of_windows_to_be()

Custom Wait

python

def custom_condition(driver):
    element = driver.find_element(By.ID, "status")
    return element.text == "Ready"

wait.until(custom_condition)

6. Advanced Actions

Action Chains

python

from selenium.webdriver.common.action_chains import ActionChains

actions = ActionChains(driver)

# Hover
actions.move_to_element(element).perform()

# Double click
actions.double_click(element).perform()

# Right click
actions.context_click(element).perform()

# Drag and drop
actions.drag_and_drop(source, target).perform()

# Click and hold
actions.click_and_hold(element).perform()
actions.release().perform()

# Chain multiple actions
actions.move_to_element(menu).click().perform()
actions.move_to_element(submenu).click().perform()

Scroll

python

# Scroll to element
driver.execute_script("arguments[0].scrollIntoView();", element)

# Scroll by amount
driver.execute_script("window.scrollBy(0, 500);")

# Scroll to bottom
driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")

# Scroll to top
driver.execute_script("window.scrollTo(0, 0);")

JavaScript Execution

python

# Execute script
driver.execute_script("alert('Hello');")

# Return value
title = driver.execute_script("return document.title;")

# With arguments
driver.execute_script("arguments[0].click();", element)

# Modify element
driver.execute_script(
    "arguments[0].setAttribute('style', 'background: red');",
    element
)

7. Frames and Windows

Frames/iFrames

python

# Switch to frame by element
frame = driver.find_element(By.TAG_NAME, "iframe")
driver.switch_to.frame(frame)

# Switch by name or ID
driver.switch_to.frame("frame-name")

# Switch by index
driver.switch_to.frame(0)

# Switch back to main content
driver.switch_to.default_content()

# Switch to parent frame
driver.switch_to.parent_frame()

Windows/Tabs

python

# Get current window
main_window = driver.current_window_handle

# Get all windows
windows = driver.window_handles

# Open new tab
driver.execute_script("window.open('');")

# Switch to new window
driver.switch_to.window(windows[-1])

# Switch back
driver.switch_to.window(main_window)

# Close current window
driver.close()

# Quit all windows
driver.quit()

Alerts

python

# Switch to alert
alert = driver.switch_to.alert

# Get text
text = alert.text

# Accept (OK)
alert.accept()

# Dismiss (Cancel)
alert.dismiss()

# Send text to prompt
alert.send_keys("input text")
alert.accept()

8. Screenshots and Files

Screenshots

python

# Full page
driver.save_screenshot("page.png")

# Element screenshot
element.screenshot("element.png")

# As base64
screenshot = driver.get_screenshot_as_base64()

# As PNG bytes
screenshot = driver.get_screenshot_as_png()

File Upload

python

upload = driver.find_element(By.CSS_SELECTOR, "input[type='file']")
upload.send_keys("/path/to/file.pdf")

File Download

python

options = Options()
prefs = {
    "download.default_directory": "/path/to/download",
    "download.prompt_for_download": False,
    "download.directory_upgrade": True
}
options.add_experimental_option("prefs", prefs)

driver = webdriver.Chrome(options=options)

9. Cookies and Storage

Cookies

python

# Get all cookies
cookies = driver.get_cookies()

# Get specific cookie
cookie = driver.get_cookie("session_id")

# Add cookie
driver.add_cookie({
    "name": "auth",
    "value": "token123",
    "domain": "example.com"
})

# Delete cookie
driver.delete_cookie("auth")

# Delete all cookies
driver.delete_all_cookies()

Local Storage

python

# Set item
driver.execute_script("localStorage.setItem('key', 'value');")

# Get item
value = driver.execute_script("return localStorage.getItem('key');")

# Remove item
driver.execute_script("localStorage.removeItem('key');")

# Clear all
driver.execute_script("localStorage.clear();")

10. Page Object Model

Base Page

python

class BasePage:
    def __init__(self, driver):
        self.driver = driver
        self.wait = WebDriverWait(driver, 10)

    def find(self, locator):
        return self.wait.until(
            EC.presence_of_element_located(locator)
        )

    def click(self, locator):
        self.wait.until(
            EC.element_to_be_clickable(locator)
        ).click()

    def type(self, locator, text):
        element = self.find(locator)
        element.clear()
        element.send_keys(text)

Page Class

python

class LoginPage(BasePage):
    # Locators
    USERNAME = (By.ID, "username")
    PASSWORD = (By.ID, "password")
    SUBMIT = (By.CSS_SELECTOR, "button[type='submit']")
    ERROR = (By.CLASS_NAME, "error-message")

    def __init__(self, driver):
        super().__init__(driver)
        self.url = "https://example.com/login"

    def open(self):
        self.driver.get(self.url)
        return self

    def login(self, username, password):
        self.type(self.USERNAME, username)
        self.type(self.PASSWORD, password)
        self.click(self.SUBMIT)
        return DashboardPage(self.driver)

    def get_error(self):
        return self.find(self.ERROR).text

Usage

python

# In tests
login_page = LoginPage(driver).open()
dashboard = login_page.login("user", "pass")
assert dashboard.is_loaded()

11. Testing Integration

pytest

python

import pytest
from selenium import webdriver

@pytest.fixture
def driver():
    driver = webdriver.Chrome()
    driver.implicitly_wait(10)
    yield driver
    driver.quit()

def test_login(driver):
    driver.get("https://example.com/login")
    driver.find_element(By.ID, "username").send_keys("user")
    driver.find_element(By.ID, "password").send_keys("pass")
    driver.find_element(By.CSS_SELECTOR, "button[type='submit']").click()

    assert "dashboard" in driver.current_url

unittest

python

import unittest
from selenium import webdriver

class TestLogin(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()

    def tearDown(self):
        self.driver.quit()

    def test_valid_login(self):
        self.driver.get("https://example.com/login")
        # Test logic
        self.assertIn("dashboard", self.driver.current_url)

if __name__ == "__main__":
    unittest.main()

12. Troubleshooting

Common Issues

StaleElementReferenceException:

python

# Re-find element after page changes
try:
    element.click()
except StaleElementReferenceException:
    element = driver.find_element(By.ID, "my-id")
    element.click()

TimeoutException:

python

from selenium.common.exceptions import TimeoutException

try:
    wait.until(EC.presence_of_element_located((By.ID, "slow")))
except TimeoutException:
    print("Element not found in time")

ElementNotInteractableException:

python

# Wait for clickable
wait.until(EC.element_to_be_clickable((By.ID, "button")))

# Or scroll into view
driver.execute_script("arguments[0].scrollIntoView();", element)

Best Practices

Use explicit waits - More reliable than implicit
Page Object Model - Maintainable test code
Unique locators - Prefer ID over XPath
Handle exceptions - Graceful error handling
Close browsers - Use quit() in finally/teardown
Headless for CI - Faster test execution
Screenshots on failure - Debug easier
Avoid hardcoded waits - Use conditions
Parallel execution - Faster test suites
Clean test data - Isolated tests

Search AI Tools

Install this agent skill to your Project

SKILL.md

Selenium Skill

Quick Reference

Supported Browsers

Key Components

1. Installation

Python

Java (Maven)

JavaScript

2. Basic Setup (Python)

Chrome

Firefox

Options

3. Finding Elements

Locator Strategies

XPath Examples

4. Interactions

Basic Actions

Keyboard Actions

Select Dropdowns

5. Waits

Implicit Wait

Explicit Wait

Common Expected Conditions

Custom Wait

6. Advanced Actions

Action Chains

Scroll

JavaScript Execution

7. Frames and Windows

Frames/iFrames

Windows/Tabs

Alerts

8. Screenshots and Files

Screenshots

File Upload

File Download

9. Cookies and Storage

Cookies

Local Storage

10. Page Object Model

Base Page

Page Class

Usage

11. Testing Integration

pytest

unittest

12. Troubleshooting

Common Issues

Best Practices