Cross browser testing is essential for ensuring that a web application functions correctly across different browsers and devices, as users are unlikely to switch browsers if a site fails to perform well. A strategic approach involves initially focusing on the four major browsers—Chrome, Firefox, Internet Explorer, and Safari—which account for 97% of internet traffic, and prioritizing the testing of critical functionalities across all platforms. Leveraging virtual environments and emulators can help address cross-platform issues, while automation testing tools can efficiently handle repetitive and complex test cases. Testing on actual mobile devices is recommended over emulators to better address responsive design challenges, with a focus on commonly used device resolutions. Ideally, cross browser testing should start early in the development process and be repeated throughout to mitigate risks and costs associated with post-production testing. Despite the complexity and potential challenges of testing a large application across numerous browser-device combinations, a well-devised testing strategy can simplify the process.