facebook open source script

download facebook videos to computer, greasemonkey?
I would be able to download Facebook videos to my computer. I try to understand and understand the whole "greasemonkey" thing. (Yes, I'm new to all this. I am not a computer professional.) Anyone willing to clearly explain the steps me? Or any other way to do it? Problem with this: When I click on this link http://userscripts.org/scripts/source/9789.user.js opens a window asking you "Save" or "cancel." When recording file does not open. He says theres an error. I'm new to this so I can please get an explanation clear?
You need to download Firefox Add-on Greasemonkey – https: / / addons.mozilla.org/en-US/firefox/addon/748 All the information you need is here http://wiki.greasespot.net/Greasemonkey_Manual:Installing_Scripts
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