Advanced Cross-Browser Testing Strategies for Addressing Legacy and Modern Browsers


Browser compatibility is vital in web development. It ensures websites work well on different browsers. Cross browser testing is crucial for this. It means testing websites on various old and new browsers to ensure they perform consistently. Legacy browsers like Internet Explorer and modern ones like Chrome pose challenges because they use different rendering engines and support web standards differently.

In this blog, let us explore advanced strategies for cross-browser testing. It is essential for ensuring a consistent user experience across browsers. We will explore various automation testing tools and methods to address compatibility issues and ensure your website performs optimally on every browser.

Cross-Browser Testing Overview

It ensures a web application works correctly on different web browsers. It ensures users have the same experience no matter which browser they use. This testing is essential because different browsers may interpret code differently, leading to potential issues in rendering and functionality.

Developers perform cross-browser testing to identify and fix browser compatibility issues. It helps in ensuring that the website behaves as expected across various browsers.

List of Legacy and Modern Browsers

Here is the list of legacy and modern browsers.

Legacy Browsers:

  • Internet Explorer (versions 11 and earlier)
  • Safari (versions before 10)
  • Firefox (versions before 50)
  • Opera (versions before 15)

Modern Browsers:

  • Google Chrome
  • Mozilla Firefox
  • Apple Safari
  • Microsoft Edge

Strategies for Advanced Cross-Browser Testing

Here are some advanced strategies for cross-browser testing addressing legacy and modern browsers.

Implement Automated Testing

Automated testing is essential for efficient cross-browser testing to validate web applications across different browsers and environments with minimal manual effort.

  • Selenium WebDriver can automate browser interactions across various browsers. It supports multiple programming languages and ensures extensive browser compatibility.
  • Puppeteer is designed for Chrome and Chromium-based browsers. It provides a high-level API to control headless and full-page Chrome environments. This makes it ideal for automated testing scenarios.
  • TestCafe offers a different approach by running tests in real browsers, supporting Chrome, Firefox, Safari, and Edge without requiring WebDriver or plugins. This simplifies the setup and usage for cross-browser testing.

These tools improve the testing process to ensure consistency and accuracy in detecting browser compatibility issues.

CSS and JavaScript Polyfills

CSS and JavaScript polyfills are essential tools for ensuring consistent functionality and appearance across different browsers in older environments that lack support for modern web standards.

CSS polyfills like Normalize.css and Bootstrap standardize CSS across browsers to ensure consistent styling and layout. These tools address browser-specific differences in CSS implementations to provide a uniform appearance for users.

JavaScript polyfills replicate newer JavaScript features in older browsers that lack native support. They enable websites to utilize modern JavaScript functionality without concerns about browser compatibility issues across different browsers.

Feature detection

Managing varying levels of support for HTML, CSS, and JavaScript features across different browsers is essential in cross-browser development. This strategy makes sure websites and web applications work the same on all browsers.

  • Modernizr checks for HTML5 and CSS3 features in the browser. It adds classes to the HTML element based on feature support to apply different styles and JavaScript based on browser capabilities.
  • CanIUse provides current browser support tables for web technologies. It lets developers check the support status of specific features across browsers and versions to aid in decision-making and provide fallbacks for unsupported features.
  • js allows developers to write conditional JavaScript based on browser support for specific features. It provides a lightweight way to handle feature detection directly in JavaScript. This makes it easier to adapt code based on browser capabilities.

Performance Testing

Performance Testing ensures a fast and responsive web application experience on various browsers.

Lighthouse reviews give suggestions on how to improve and page based on different performance measures.

WebPageTest lets you run free speed tests for your website using detailed metrics on performance, how resources load, and timelines to pinpoint browser compatibility issues and improve performance.

  • Lighthouse reviews web pages for performance, accessibility, progressive web apps, SEO, and more. It gives suggestions on how to improve and rates your page based on different performance measures.
  • WebPageTest lets you run free speed tests for your website from various global locations using real web browsers. It gives you detailed metrics on performance, charts showing how resources load, and timelines to pinpoint browser compatibility issues and improve performance.

User-Agent Testing

This testing involves adapting web content based on the user-agent string sent by a browser. This string identifies the browser type, version, and operating system to tailor content and functionality accordingly.

  • Server-side detection analyzes the user-agent string on the server to deliver content optimized for specific browsers. This method ensures different content versions are served based on detected browsers.
  • Client-side detection uses JavaScript to dynamically adjust web application content or behavior based on the user-agent string detected in the client’s browser. It allows for customized user experiences without server-side processing.

 Polyfill libraries help to provide modern JavaScript features and APIs in older browsers that do not support them natively. This ensures consistent functionality and performance across different browser versions.

Responsive Testing

It ensures that web applications are displayed correctly and function properly on various devices and screen sizes.

 Responsive Design Checker visualizes how their website appears on different devices and ensures it adjusts properly to various environments.

  • Viewport Resizer allows developers to test responsive design directly in the browser. It offers an easy way to adjust the viewport to different device sizes to ensure websites adapt properly to various screen dimensions.

These tools are essential for verifying and optimizing the responsive design to ensure a consistent user experience across all devices.

Cloud Testing Platforms

Cloud platforms are invaluable resources for achieving comprehensive browser compatibility. These platforms provide virtualized browsers and devices to test their web applications across multiple browser versions and operating systems without needing physical devices.

Developers can ensure that their applications perform consistently across diverse environments, including legacy browsers and the latest releases, by using these platforms. Cloud platforms offer features such as real-time interaction with browsers, automated testing capabilities, and detailed debugging tools.

These platforms enable collaboration among team members by allowing them to share test results and collaborate on issue resolution. They also provide scalability to run tests in parallel and speed up the testing process.

An AI-powered test execution platform like LambdaTest proves to be more scalable and cost-effective. LambdaTest provides access to an online browser farm comprising over 3000 combinations of browsers and operating systems for automation testing.

Key features of LambdaTest for you include:

  • Access to an extensive online browser farm containing over 3000 browsers and operating systems, facilitating comprehensive cross-browser compatibility testing.
  • Assurance of reliable test results with superior hardware ensuring consistent performance. LambdaTest holds SOC2 Type2 certification and GDPR compliance, guaranteeing the security of your data.
  • Automated report generation in multiple formats for you, enabling accurate and efficient analysis.
  • Real-time progress tracking on a dashboard for you and seamless integration with project management tools, keeping you updated on your team activities.
  • Integration compatibility with over 200 project management tools and more, offering extensive integration options for you

Visual Regression Testing

It’s a method used to find unintended visual changes in a web app. It compares screenshots of the current and previous versions of a web page to spot any visual differences caused by code changes or updates.

This testing method is important for keeping the look and feel consistent across various browsers and devices. It helps developers find issues like layout changes, font differences, or color mismatches that can affect how a website appears.

Tools like BackstopJS and Percy automate the process by taking screenshots of web pages and showing any visual differences between versions.

This helps developers quickly find and solve issues before users notice them. Visual regression testing ensures that the appearance of a web application stays consistent in improving user satisfaction.

Continuous Integration

It allows developers to frequently merge their code changes into a central repository which is then automatically tested. This practice helps teams identify and fix issues early in the development cycle.

Tools like Jenkins and Travis CI automate building, testing, and deploying applications. They ensure that new code blends well with existing code and that all tests pass before deployment.

It helps developers verify that changes to the codebase don’t introduce errors or disrupt existing functionality. This practice increases code quality and encourages teamwork among team members.

It allows teams to release software updates more often and with fewer bugs to make applications more reliable and stable. It’s an important practice for modern software development teams looking to improve efficiency and code quality.

Version Compatibility

Ensuring version compatibility is crucial in web development to guarantee that websites and applications work across different software versions. Developers need to test their code against various versions of browsers to avoid issues.

Developers can test websites on different browser versions using virtual environments. These tools allow developers to identify and fix browser compatibility issues early in the development process and they can also use version managers to switch between different language versions. This ensures that the code works across different environments without browser compatibility problems.

Testing version compatibility early and using appropriate tools help developers ensure that their websites and applications work smoothly across various versions of browsers.

Focus on Accessibility

It ensures web applications are usable by people with disabilities. It ensures all users can navigate, understand, and interact with the content.

Developers make websites more accessible by using clear HTML tags, adding alt text for images, and ensuring keyboard navigation works well. These steps help people with disabilities use the website easily.

Developers should use tools like Axe, aXe-core, and WAVE alongside web accessibility guidelines to test and fix issues to ensure the website is accessible and usable for everyone.


In conclusion, Cross-browser testing ensures web applications work across all browsers and devices. By using various testing tools and methods, developers can find and fix browser compatibility issues early in development. Tools like Selenium WebDriver and Lighthouse automate testing and give clear advice on how to improve.

Continuous integration practices enable teams to integrate and test code continuously to ensure new features and updates are deployed without introducing errors. This approach improves code quality, enhances collaboration, and increases efficiency among team members. Implementing these best practices helps developers deliver reliable, quality web applications that provide a better user experience across all platforms.