How to Use Css Selectors in Selenium?

Best practices

Use specific and unique CSS selectors to improve the accuracy and performance of element retrieval.
Opt for class selectors (`.class-name`) for elements with common styles, and ID selectors (`#id-name`) for unique elements, ensuring faster and more reliable element selection.
When selecting elements based on attributes, ensure to use the attribute value that uniquely identifies the element, like `[type='submit']` for buttons.
Combine CSS selectors to navigate DOM hierarchies, such as `.parent-class .child-class`, to target specific elements within a nested structure efficiently.

from selenium import webdriver
from selenium.webdriver.common.by import By

# Initialize WebDriver
driver = webdriver.Chrome()

# Navigate to a webpage
driver.get("https://sandbox.oxylabs.io/products")

# Select element by CSS class
product_name = driver.find_element(By.CSS_SELECTOR, ".product-name")
print(product_name.text)

# Select element by ID
product_id = driver.find_element(By.CSS_SELECTOR, "#product-id")
print(product_id.text)

# Select elements by attribute
price = driver.find_element(By.CSS_SELECTOR, "[data-price='value']")
print(price.text)

# Combining CSS selectors
info = driver.find_element(By.CSS_SELECTOR, ".product-info .info-details")
print(info.text)

# Close the browser
driver.quit()

Common issues

Ensure your CSS selectors are updated to match any changes in the webpage's structure or style to avoid stale element reference errors.
Avoid using overly complex CSS selectors which can lead to slower execution times and harder maintenance; simplify where possible.
Use pseudo-classes like `:first-child`, `:last-child`, or `:nth-child(n)` to target specific elements in a list or among siblings for more precise control.
Regularly test and validate your CSS selectors in the browser's developer tools before implementing them in your Selenium scripts to catch any potential issues early.

# Bad example: Using outdated CSS selector
old_price = driver.find_element(By.CSS_SELECTOR, ".old-price-label")

# Good example: Updated CSS selector after webpage changes
current_price = driver.find_element(By.CSS_SELECTOR, ".current-price-label")

# Bad example: Overly complex CSS selector
complex_selector = driver.find_element(By.CSS_SELECTOR, "body > div > div > div > ul > li > a")

# Good example: Simplified CSS selector
simple_selector = driver.find_element(By.CSS_SELECTOR, ".menu-item > a")

# Bad example: Selecting the first item without using pseudo-classes
first_item = driver.find_elements(By.CSS_SELECTOR, ".item-list li")[0]

# Good example: Using :first-child pseudo-class
first_item = driver.find_element(By.CSS_SELECTOR, ".item-list li:first-child")

# Bad example: Not testing CSS selector in browser before use
untested_selector = driver.find_element(By.CSS_SELECTOR, ".unverified-selector")

# Good example: Manually verify selector works in browser's developer tools first
verified_selector = driver.find_element(By.CSS_SELECTOR, ".verified-selector")