Here are some Firefox browser plugins that I find useful.
- Firebug
The ultimate on the fly web developer tool. Inspect page elements, edit css, disable scripts and much, much more. - Html Validator
Spot those repeated IDs, unescaped divs and markup errors. - JSView
Useful for investigating javascript source files and errors. - Screengrab
Quick and easy screengrabs of your screen. - Yslow
See what is causing your site to load slowly and look at ways to optimise page load. - Web developer
Has been overtaken by Firebug in recent years, but still useful for its ruler, css editing and element selector.
