If you're into Web Development or thinking of jumping into it, here's a tool I use on a daily basis. Firebug, is a must have Firefox extension which has the ability to inspect various elements on a web page. Once activated, hover your mouse over an element and Firebug will give you loads of detail on that item. Check out where it resides in your XHTML, CSS rules belonging to it, edit Javascript, and more. It is a must have tool for Web Developers in general.
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