To all my friends, who are web developers and frequently have problems debugging their code, I would strongly recommend using Firebug Debugger.
It is an amazing tool that integrates well with Firefox and is capable of editing, debugging and monitoring Javascript, CSS, HTML, DOM API, and AJAX. Some of its widely used features:
- Logging for web pages - get rid of alert boxes
- JavaScript Debugging
- Ajax Request Spy - can log all Ajax request and response messages
- Live Editing - let you edit some parts of DOM
So what are you waiting for. Get Firebug Now!!
An excellent tutorial about Debugging JavaScript with Firebug can be found here.
I do not understand why Gmail shows up this ugly warning when using Firebug with it:
May be because Gmail makes excessive use of technologies like Ajax and JavaScript and if Firebug is actively trapping all Ajax request-response traffic, then it might just eat up a substantial portion of your RAM after being active for a longer time.