Testing with the Selenium IDE is the easiest way but only works with firefox, that means no cross browser testing.
After you have installed the Selenium extension, You can run tests directly by calling the following url in your firefox browser:
where baseURL is the location of the web site to test and test is the start location of the test suite, means the code of the tests generated with the Selenium IDE.
To write tests or debug existing tests start the extension and load your test or create a new one.
In addition, the Selenium IDE provides the possibility to export written tests in one of the following programming languages: PHP, Java, .NET, Perl, Python, and Ruby.