How does the DiggBar dynamically resize its iframe's height based on content not on their domain?

Question

Someone has already asked, How does the DiggBar work? in a previous question.

While someone provided a decent answer it didn\'t address one thing:

Answer 1

Part of the problem with HTML you can't just set an element of any thing to 100% height and have it take up the whole window space. One way to do this is by making the body have a pixel height of the window and any thing inside the body set to 100% will be the size of the window.

Basically just make a JavaScript that ties onto the windows onresize event and have it resize the body to to the size of the window.

here is an example I made using jQuery

With this you will be able to set a div or another elements and have it work at the full height of the window.