Selenium Core is a test tool for web applications. Selenium Core tests run directly in a browser, just as real users do. And they run in Internet Explorer, Mozilla and Firefox on Windows, Linux, and Macintosh. No other test tool covers such a wide array of platforms.

* Browser compatibility testing. Test your application to see if it works correctly on different browsers and operating systems. The same script can run on any Selenium platform.
* System functional testing. Create regression tests to verify application functionality and user acceptance.

Selenium Core uses a unique mechanism which allows it to run on so many platforms. Written in pure JavaScript/DHTML, you copy Selenium Core tests directly into your your application webserver, allowing the tests to run in any supported browser on the client-side. Thus, you must have write access to the machine your web application server is running on to install Selenium Core.