There are a lot of misconceptions about how the Firefox extension Greasemonkey works and what it does to a web site.  Many users are not even sure how it actually works.  Some think it actually changes the web site on the server side, others think the web site changes for the script every time they visit and some even think that without the Firefox script, the web site would not work at all.

Greasemonkey, once installed, allows you to install numerous scripts to change the way your browser interacts with a web site. Once a given script is installed and you restart Firefox, you can begin to visit web sites and see how that script works for you. Basically, when you go to a web site, Greasemonkey kicks into action and loads the script as the page loads, changing how the HTML code of the site interacts with the browser to display the changed web site for you.

This change only occurs in your Firefox browser and it works each session you visit the web site. It does not change any coding on the server side, to the web site itself or any other aspect of the web pages you visit. It simply changes how Firefox reads the code on the page, redisplays it the way the script directs and then that is what you begin to visit. Every time you visit the web site, the script changes the page for you without noticing it. There is no delay in the changes visible to the naked eye.

Greasemonkey makes it easier for you to get the most out of your favorite web sites.  These little changes here or there, and sometimes larger ones, make using the Internet even more personal for those surfing it.  These changes make your interaction with given web sites the way you always wanted it to be, and with Greasemonkey, that is now possible.