fun with the add-on firebug.

first, if you haven't already got mozilla firefox i suggest you go and download it.

once you have got mozilla firefox go and download this add-on below:
https://addons.mozilla.org/en-us/firefox/addon/1843

now just follow the tutorial below.
here is a very quick tutorial: (may need to pause)
http://youtube.com/watch?v=dvoyjokodqc