It is time you know about Greasemonkey, if you havent heard about it already. Greasemonkey is a Firefox extension which lets you to add bits of DHTML (“user scripts”) to any webpage to change it’s behavior. In much the same way that user CSS lets you take control of a webpage’s style, user scripts let you easily control any aspect of a webpage’s design or interaction.
“That capability has gained the extension an avid following of Web surfers who want to customize the sites they visit, removing design glitches and stripping sites of ads. But the extension comes with substantial security risks and could stir trouble among site owners who object to individual, custom redesigns of their pages.”
Greasemonkey scripts can perform a host of tasks on multiple websites according to the GreaseMonkey UserScripts page. You can install scripts by right-clicking on links to them and selecting “Install User Script…”. Or, you can select the same option under the tools menu while viewing the contents of a user script file. Also you can write your own userscript with just a few steps. If you cant make it, then request it and other technical wizards might make it for you.