What is cross-browser compatibility, and why should you care?

What is cross-browser compatibility, and why should you care?

Picture this scenario: You worked hard to build your company's website or app, and it worked. It seems to be functioning. A few days later, the product team informed you that people reported that the website looked terrible on the Edge browser in Windows, and several functionalities are not working.

“But everything works fine on my machine,” you might say. The machine referred to might be a 2021 M1 MacBook Pro, yet the user complaining may be using a 2015 Windows 10 laptop or something else. How do you tackle this issue? How do you ensure your websites and web apps are compatible with all other browsers and devices, not just the one you used for developing? This article will discuss cross-browser compatibility and its significance, methods to ensure compatibility, and practical tips for ensuring cross-browser compatibility in your websites.

What is Cross-Browser Compatibility?

Cross-browser compatibility is the ability of your website or web application to function consistently and correctly across various devices and web browsers. It ensures that browsers like Google Chrome, Mozilla Firefox, Apple Safari, Microsoft Edge, and others interpret and render your website uniformly.

Common Causes of Cross-Browser Compatibility Issues

  1. Different Browser Rendering Engines:

Each browser employs its rendering engine (e.g., Blink for Chrome, WebKit for Safari, Gecko for Firefox). These engines may interpret and display website code differently.

  1. Different Devices:

Different devices, such as Laptops, Tablets, and smartphones, display your website differently to their user.

Why Cross-Browser Compatibility Matters

As a developer, understanding the importance of cross-browser compatibility is essential for several reasons:

  1. User Experience: A seamless experience across different browsers contributes to positive user experiences, which in turn impact user satisfaction and business success. If a user visits your website and notices things are not displayed correctly, it might give them a bad experience and deter them from revisiting it.

  2. Reach Diverse Users: The internet's diversity means users access content via various browsers and devices. Compatibility ensures your website reaches a broader audience.

    Statistic of browsers used to access the internet. Source: StatCounter

  3. Better SEO: Search engines favor websites with consistent positive experiences across browsers. Neglecting compatibility can adversely affect search rankings.

  4. Future-Proofing Your Code: Evolving browsers introduce new features. Cross-browser compatibility ensures your application remains functional amid these changes.

Tips for Ensuring Cross-Browser Compatibility

  1. Use Modern Web Standards

    Your HTML, CSS, and JavaScript code and website accessibility should follow the standard web practices, reducing the likelihood of compatibility issues with browsers. The World Wide Web Consortium (W3C) develops open standards to ensure the long-term growth and accessibility of the World Wide Web. Following these standards will help ensure your website is compatible with the standard web browser.

  2. Practice Responsive Design

    Implementing fluid layouts, flexible images, and CSS media queries to provide a consistent user experience across various devices. These will help to make your website responsive to different devices that your users will visit from

  3. Validate Your Code

    Include tools like W3C code validation service and CSS validator to ensure your code meets web standards.

  4. Test Early, Test Often

    Begin cross-browser Testing in the early stages of development to identify and address these issues. Frequent Testing can help you catch issues before they turn into significant problems.

Consider Using CSS Resets

Use CSS resets to establish a baseline layout across browsers and minimize inconsistencies. Each browser has predefined padding, margin, and line height styles by default. Etc. Applying CSS resets before adding custom styling to your webpage helps you predict how elements render comfortably across different browsers.


1. Use a box-sizing model.
*, *::before, *::after {
    box-sizing: border-box;
2. Removes the default margin and padding on the browsers
    margin: 0;
    padding: 0;

You can also consider using stylesheets like Normalize.css, Eric Mayer's CSS reset rules to establish a baseline layout across browsers.

How to Test for Cross-Browser Compatibility

  1. Create a Plan: Based on audience research, determine target browsers and establish what your website should look like, what devices they would be using, and what browsers are primarily used in the region where your intended users will be. Having a plan will help you decide which browsers to test.

  2. Development: Strive for uniform functionality across all target browsers. Or use polyfills as needed. Some Browsers interpret your code differently on some styling features, so you should try styling them using browser-specific code; you can do this using prefixes. Some general prefixes used when targeting specific browsers are:

    • Safari and Chrome (-WebKit)

    • Internet Explorer (-ms)

    • Opera (-o)

    • Mozilla Firefox (-moz)

  3. Testing: There are two types of Testing you should consider when performing cross-browser compatibility tests

    • Manuel Testing: This involves using live devices and browsers to test for functionality and consistency of your website. Consider using tools like BrowserStack and Lambdatest, which provide different device stimulations and browsers to identify inconsistency and performance issues on your website. And automated Testing using tools like Selenium

    • Automated Testing: This involves using automated scripts and tools to execute test cases and verify the functionality of your website on different browsers and devices. Some automated tools you can consider when performing cross-browser compatibility tests are Playwright and Selenium

Pitfalls to Avoid in Cross-Browser Compatibility

There are a couple of pitfalls to avoid when ensuring your websites and web applications are cross-browser compatible; because cross-browser compatibility can be tedious, it's easy to fall into these pitfalls

  1. Over-Engineering: Focus more on the core functionality of your website and the user experience it provides for your users rather than pursuing pixel-perfect consistency across all browsers. This will help you avoid over-engineering your product to target specific browsers.

  2. Ignoring Older Browsers: Balance dropping support for outdated browsers with considering your target audience's browser usage. For example, Microsoft retired the Internet Explorer browser in favor of its new Edge browser, so it wouldn't be wise to spend time making your website compatible with browsers like Internet Explorer that are no longer supported.

  3. Misusing Polyfills: While using polyfills can help you to implement features that are not present in a browser and flatten the browser API landscape, you should only use it judiciously for critical missing features to avoid unnecessary code bloat that might hurt your website performance.

Testing in Isolation: To better understand how your website will function in different environments. Test not only on individual browsers but also various combinations of devices and screen sizes.

Best Practices for Cross-Browser Compatibility

  • Research Your Audience: Perform market research to understand your target audience's browser preferences based on their region. Do not test randomly with browsers, as this might not be adequate for your users.
  • Prepare a Browser List To Test on: Limit development and test coverage efforts to a specific set of browsers relevant to your audience. A list of browsers will help you focus on pertinent issues for your target audience and reduce exposure to cross-browser bugs.

  • Choose the Right Automation Tool: Since cross-browser compatibility testing is a tedious task and requires a lot of time and effort, consider selecting tools that are easy to use and allow Testing across a maximum number of browsers for maximum efficiency.

  • Test on Real Device Browsers: Automated Testing should differ from manual Testing. Testing on actual device browsers will help you identify bugs that may arise on actual devices that your end-users will use, offering a more realistic testing environment.


Cross-browser compatibility is not just a checkbox; it's a journey of continuous improvement. By understanding its significance and following best practices, you can navigate this complex landscape, creating websites and software that provide a seamless experience for users across different browsers and devices.

Happy coding!

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