This is an oldie but goodie, that for sure works in Firefox...
Visit Conveniently searching Wikipedia, and follow the instructions for your browser. It's a bookmarklet that sits on your toolbar, and which serves as a Wikipedia search button that you can activate from any web page. The next time you want to look something up on Wikipedia while browsing a web-page, highlight the term and then click on your new bookmarklet.
While it is important to remain civil to all users, please remember that new users may not be familiar with Wikiquette. So if you encounter a mistake by a new user please do not bite the newbie.
This editor is an Apprentice Editor and is entitled to display this Service Badge.
D:<
Nothing annoys this user more than when a teacher says that Wikipedia isn't reliable and that anybody can enter anything completely untrue that'll stay.
This user has been meaning to join the Procrastinators' Club for several years.
Hi, this is my user page.
I have been editing Wikipedia during my free periods at school to pass the time. I have created a script which decapitalizes the selected text when a button on the source editor toolbar is pressed.