Cross Browser Testing in Selenium: How to Get Started

Cross browser testing in Selenium helps teams ensure their websites work smoothly for everyone, no matter which browser or operating system they use. From Chrome to Safari, Firefox to Edge, each browser interprets code a little differently. Even the same browser can behave in surprising ways across versions or devices.

That’s where Selenium WebDriver comes in. It allows you to write test scripts once and run them across multiple browsers to verify that layout, functionality, and performance remain consistent.

In this guide, we’ll walk you through:

• What Selenium WebDriver is and how it fits into the ecosystem
• What cross browser testing in Selenium really means
• How to set it up and run tests on different browsers
• Best practices for scaling with real devices and cloud platforms
• Why platforms like Katalon make Selenium testing even more efficient

Let’s get started!

What is Selenium WebDriver?

Selenium WebDriver is an open‑source automation tool that mimics real user actions in browsers such as clicking links, typing into fields, navigating pages. It supports multiple languages like Java, Python, C#, and more.

This cross‑language flexibility means teams can write tests in the language they already know and apply them across different browser types.

How does Selenium WebDriver work?

WebDriver interacts directly with the browser it controls. It can run tests on real browser instances using specific drivers like ChromeDriver for Chrome or GeckoDriver for Firefox. That gives it both precision and reliability and confirms that your automation runs the same way a user would.

WebDriver fits into the Selenium ecosystem as the powerhouse of programmatic automation. Selenium IDE is better for quick record‑and‑play tasks. Selenium Grid enables running WebDriver tests in parallel across machines.

In a way, WebDriver is your test logic engine, IDE gives you start‑up speed, and Grid handles scale.

What is cross-browser testing in Selenium?

Cross browser testing in Selenium means checking that a website or application works the same way across different browsers, browser versions, and operating systems. WebDriver scripts help automate this validation by running the same test on Chrome, Firefox, Safari, Edge, and more. Selenium ensures your site behaves reliably for every user.

Cross-browser testing catches real-world issues that are hard to spot otherwise. Some examples of it are:

• Broken layouts when CSS is interpreted differently between browsers. Browsers handle box models, margins, and flex layouts in slight variations, which affects visual alignment.
• Inconsistent JavaScript execution due to varying browser engines. Some browsers may not support newer features or handle code quirks the same way.
• Unsupported or partial CSS features that look or behave differently from one browser to another.

With WebDriver, you can automate those checks instead of clicking through each browser manually. That gives you consistent coverage and saves time, so your cross-browser testing process becomes  much more reliable and easy to scale.

Why is Cross Browser Testing Important?

Each browser processes HTML, CSS, and JavaScript through its own engine:

• Chrome uses Blink.
• Firefox uses Gecko.
• Safari uses WebKit.

These engines render the same code with subtle differences, and users switch between devices and browsers all the time. A customer might browse your site on Chrome during lunch, then reopen it on Safari at home. With cross browser testing, you can check that every feature still works perfectly in both places.

How does Selenium help with Cross Browser Testing?

Cross-browser testing with Selenium WebDriver

Selenium WebDriver is a widely used tool for automation testing, and one of its key capabilities is cross-browser testing. This feature lets you ensure that your web application works consistently across different browsers. Below is a detailed breakdown of how to perform cross-browser testing using Selenium WebDriver.

Step 1: Automate test cases across multiple browsers

Begin by writing your test cases with Selenium WebDriver. Each major browser (Chrome, Firefox, Edge, Safari, Internet Explorer) requires its own WebDriver executable, which acts as a bridge between Selenium and the browser.

You’ll need to download and configure the appropriate WebDriver for each browser. For example, use chromedriver for Chrome, geckodriver for Firefox, and msedgedrive for Edge, and so on.

Step 2: Integrate TestNG for Parallel and Parameterized Execution

Running your test cases sequentially on each browser is time-consuming. TestNG, a popular testing framework for Java, solves this by allowing you to parameterize your tests and execute them in parallel. By adding the @Parameters annotation, you can pass the browser name from an external configuration file (like testng.xml) into your test script at runtime. This lets you use a single test class for multiple browsers.

Additionally, TestNG’s parallel attribute in the suite configuration enables running the same test case simultaneously on different browsers, speeding up the cross-browser validation process.

Step 3: Write the Test Script with Dynamic Browser Handling

Create a single Java test class that handles multiple browsers by using conditional logic in the setup method. Depending on the browser parameter passed in, instantiate the appropriate WebDriver (ChromeDriver, FirefoxDriver, EdgeDriver, etc.). Then write your test method to navigate to the target URL, perform the required actions, and assert the expected results.

This setup ensures that the same test logic is reused across all specified browsers. Once done, you’ll link this test class to a testng.xml file that specifies which browsers to run and enables parallel execution.

Sample Java Test Script

This Java class dynamically selects the browser based on a parameter passed from TestNG. It opens Katalon's homepage and verifies the page title for Chrome, Firefox, and Edge.

package com.qa.testcases;
import java.time.Duration;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.edge.EdgeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.testng.Assert;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.Parameters;
import org.testng.annotations.Test;

public class CrossBrowserTestingScript {
    WebDriver driver;

    @BeforeTest
    @Parameters("browser")
    public void setup(String browser) throws Exception {
        if (browser.equalsIgnoreCase("firefox")) {
            driver = new FirefoxDriver();
        } else if (browser.equalsIgnoreCase("chrome")) {
            driver = new ChromeDriver();
        } else if (browser.equalsIgnoreCase("edge")) {
            driver = new EdgeDriver();
        } else {
            throw new Exception("Incorrect Browser");
        }
        driver.manage().timeouts().implicitlyWait(Duration.ofSeconds(5));
    }

    @Test
    public void verifyTitle() {
        driver.get("https://katalon.com/");
        System.out.println("Title is: " + driver.getTitle());
        Assert.assertEquals(driver.getTitle(),
            "AI-powered automation testing tool | Katalon");
        driver.quit();
    }
}

TestNG XML Configuration

This testng.xml file defines three tests (Chrome, Firefox, Edge) and passes the browser name to your script. It also enables parallel execution of your tests.Best practices to do Cross Browser Testing in Selenium.

Best practices when doing cross browser testing in Selenium

• Use Selenium Grid or cloud platforms for scaling
  Running tests in parallel on multiple machines saves time and increases browser coverage.
• Automate high-priority user flows first
  Focus automation on business-critical paths such as login, search, and checkout. These are the most visible to users and offer the highest return on testing effort.
• Avoid hardcoding browser drivers
  Load browser types and driver paths from configuration files or environment variables. This makes your tests flexible and easy to run across different setups without code changes.
• Combine automation with manual exploratory testing
  Automated tests ensure consistency, while manual sessions help uncover edge cases and visual issues. Together, they create a strong, well-rounded test strategy.
• Use CI/CD pipelines to trigger cross browser tests automatically
  Integrate Selenium tests into your CI/CD flow. This ensures cross browser coverage happens continuously with every build or deployment, catching issues early.
• Maintain reusable test scripts
  Write modular test cases using page object models or custom libraries. This approach keeps scripts clean and easy to update as your application grows.

Following these best practices ensures that your cross browser testing in Selenium remains scalable, reliable, and aligned with real-world usage.

Why choose Katalon to automate cross-browser tests?

Katalon brings the full potential of Selenium to life through a low-code automation platform that works for teams of all experience levels. While Selenium WebDriver is a powerful tool for cross browser testing, Katalon simplifies the process from test creation to execution, reporting, and maintenance.

• Unified Platform
  Build and manage automation tests, test objects, data sets, and reports in one cohesive workspace. Katalon’s unified interface makes it easy to keep everything organized and accessible.
• Cross-Browser & Cross-Platform
  Run tests seamlessly across Chrome, Firefox, Safari, Edge, and even different operating systems, without the hassle of downloading and configuring drivers manually.
• Scalability
  Execute tests in parallel using integrations with Selenium Grid, cloud-based test platforms, or your CI/CD pipelines. This setup accelerates your test cycles while ensuring full browser coverage.
• Smart Test Maintenance
  Katalon uses AI-powered self-healing locators that automatically adjust when UI elements change, keeping your cross browser tests stable and consistent across updates.
• Reporting & Analytics
  Access built-in dashboards and export detailed test reports. Use analytics to track performance, test coverage, and release readiness with confidence.

Katalon enhances every layer of Selenium-based automation. It reduces the technical overhead while maximizing the coverage, speed, and reliability of cross browser testing. Explore more at Katalon Docs and learn from hands-on courses at Katalon Academy.