getCssValue()

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Overview

The getCssValue() method in Selenium WebDriver is used to retrieve the value of a specific CSS property applied to an element. This method is particularly useful when you want to verify or extract style-related information (such as color, font size, padding, margin, background, etc.) from an element on the web page. It helps testers check the visual appearance of elements in relation to their styles defined in the CSS.

Unlike getAttribute(), which retrieves the value of an HTML element’s attribute, getCssValue() specifically targets the CSS property values, which are typically defined in style sheets or inline styles.

Syntax

				
					String cssValue = element.getCssValue("propertyName");

propertyName: The name of the CSS property you want to retrieve (e.g., "color", "font-size", "background-color", etc.).
The method returns a String containing the value of the CSS property. If the property is not set or does not exist, it returns an empty string.

Usage

The getCssValue() method is often used when you need to verify visual styling, compare styles between different elements, or ensure that styles are applied correctly after performing an action on a web page.

Some common use cases include:

Verifying Text Color: You can use getCssValue() to check the color applied to text elements (e.g., paragraphs, buttons, etc.).

				
					WebElement button = driver.findElement(By.id("submit"));
String buttonColor = button.getCssValue("color");
System.out.println(buttonColor); // Output the color of the button text

2. Checking Background Color: It’s often necessary to verify the background color of elements, especially in tests for visual feedback after actions such as form submission or hover events.

				
					WebElement div = driver.findElement(By.id("promo-banner"));
String backgroundColor = div.getCssValue("background-color");
System.out.println(backgroundColor); // Output the background color of the element

3. Validating Font Size: When testing UI elements, you may need to validate that the font size of a heading or paragraph matches the expected value.

				
					WebElement heading = driver.findElement(By.tagName("h1"));
String fontSize = heading.getCssValue("font-size");
System.out.println(fontSize); // Output the font size of the heading

4. Verifying Border Style: getCssValue() is helpful when you need to ensure that an element’s border is applied correctly, such as checking if a form input is highlighted with a border color after an error.

				
					WebElement input = driver.findElement(By.id("email"));
String borderStyle = input.getCssValue("border");
System.out.println(borderStyle); // Output the border style of the input field

5. Checking Element Visibility: You can also check properties related to visibility, such as whether an element is displayed or hidden, by checking the display CSS property.

				
					WebElement element = driver.findElement(By.id("banner"));
String displayValue = element.getCssValue("display");
System.out.println(displayValue); // Output the display property of the element (e.g., block, none)

Example

				
					import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;

public class GetCssValueExample {
    public static void main(String[] args) {
        // Set path to the ChromeDriver executable
        System.setProperty("webdriver.chrome.driver", "path/to/chromedriver");

        // Initialize ChromeDriver
        WebDriver driver = new ChromeDriver();

        // Navigate to a page
        driver.get("https://www.example.com");

        // Find an element and get its background color
        WebElement element = driver.findElement(By.id("promo-banner"));
        String backgroundColor = element.getCssValue("background-color");
        System.out.println("Background color: " + backgroundColor); // Output the background color

        // Find an input field and get its border style
        WebElement inputField = driver.findElement(By.id("username"));
        String borderColor = inputField.getCssValue("border");
        System.out.println("Border style: " + borderColor); // Output the border style of the input field

        // Close the browser
        driver.quit();
    }
}

Importance

The getCssValue() method is important for several reasons:

Verifying UI Consistency: It allows testers to check that the visual presentation of elements is consistent with the design specifications.
Testing Styling Changes: It can be used to ensure that CSS changes triggered by user interactions (e.g., hover, focus, active states) are properly applied.
Cross-Browser Compatibility Testing: By checking CSS values, you can ensure that styling is applied correctly across different browsers, especially when styles depend on specific browser behaviors.
Ensuring Accessibility: CSS properties like color or background-color are vital for making sure text is legible and accessible, especially for users with visual impairments. The method can help verify that these are correctly set.

Limitations

Not All Properties Are Directly Accessible: Some properties (such as pseudo-elements like ::before or ::after) might not be accessible using getCssValue(). In these cases, you may need to use JavaScript execution to fetch such values.
Requires Full Style Calculation: The method returns the computed value of the CSS property, meaning it reflects the final style after all inheritance, cascade, and media query evaluations. It doesn’t give you the original value set by the developer in the CSS file.
Does Not Handle Dynamic Styles Well: If CSS changes dynamically through JavaScript or animations, the method may return outdated or unexpected values unless the element has finished the animation or transition.

Conclusion

The getCssValue() method in Selenium WebDriver is a useful tool for verifying and extracting style-related information from elements on a web page. It helps ensure that the UI is styled according to the expected design specifications, and it is essential for tasks like validating button colors, font sizes, background colors, borders, and more. This method plays a crucial role in cross-browser testing, UI consistency, and visual validation of web applications.

Key Features

Retrieves CSS Properties: getCssValue() allows fetching computed CSS values for various properties such as color, background-color, font-size, border, etc.
Validates Visual Design: It is particularly useful for testing that the visual design of web elements (such as colors, spacing, fonts) is correctly applied during automated tests.
Cross-Browser Testing: Helps ensure that styling is consistent across different browsers by validating CSS properties that affect the appearance of elements.
Real-Time CSS Computation: Returns the computed value of a CSS property, reflecting any inherited or dynamically applied styles.