Hilite Form Text

Hello,
I am so lost, i cant find anything on the net relating to this so i though i would ask someone,

I dont know how to make the function, i would like it so that when the user enters the text it searchs the text on the page and hilites behind the text yellow. So its a bit like a "find" function that hilites behind the word that it is asked to find.

I dont think that JS can do this but i thought i would ask anyways,
Thanks.

It can, but browser can do it better and faster....

yeah, but im using an HTA application so... its a we bit harder.