A Cross Browser Testing Developer tests web applications across multiple browsers to ensure their functionality and consistency. They verify that the application works effectively on different browsers, devices, and operating systems, including mobile and desktop versions. They identify and fix compatibility issues, enhancing user experience. This testing involves checking elements like layout, design, response time, and features. They use automated tools and manual testing to spot and rectify discrepancies. Their role is crucial in ensuring that all users, regardless of the browser or device they are using, have a seamless and consistent experience on the web application.