on mouse over javascript

IF you go to http://www.ilor.com and enter some thing to search. In the search results page, if you put your mouse over the links (search results) then a tiny window appears with information. I looked at their code and it is a javascript which is not there. Can anyone help me how to write this javascript or any website I can see this javascript?

The source code is here: http://www.ilor.com/js/BothHLCommonTrack.js

also, take a look at Dynamicdrive: http://www.dynamicdrive.com

Thank you very much for your help. :)