Selenium IDE for Firefox

Selenium IDE is an integrated development environment for
Selenium tests. It is implemented as a Firefox extension, and allows
you to record, edit, and debug tests. Selenium IDE includes the entire
Selenium Core, allowing you to easily and quickly record and play back
tests in the actual environment that they will run.

Selenium IDE is not only recording tool: it is a complete IDE.
You can choose to use its recording capability, or you may edit your
scripts by hand. With autocomplete support and the ability to move
commands around quickly, Selenium IDE is the ideal environment for
creating Selenium tests no matter what style of tests you prefer.

Selenium IDE