Does anyone know the code for this? I tried to look around but not knowing what the technical term for this is I failed miserably.

I think it is something to do with javascript but I am not sure. If anyone can help me thank you x 100!! :) I will credit you on my website, how you want to be credited.

you can specify the same color and background color in your css, it won't validate, but it will work.

Yep...just change the text you want visible only when highlighted to the color of your background =) That's the only way to do it that I know of.

So, for example, if you have a black background, use this code to change the text you want highlighted:

<font color="#000000">Whoo hoo! I'm being highlighted!</font>

Hope that helps! :D

See:

http://www.seologic.com/faq/hidden-text.php