You want to REMOVE, or hide the body? Technically this shouldn't be possible because you need to append the div to the body in order to see it. What you could do is create a 'mask' layer that covers the WHOLE body, then use z-index for your div to display it on top of the body.

Something like:

http://www.queness.com/post/77/simple-jquery-modal-window-tutorial

might help!

To completely hide the page all you would need to do is change line 21:

$('#mask').fadeTo(slow,0.8);

in the javascript to:

$('#mask').fadeTo(slow,1);

and the color of the mask on line 7 of the CSS can be changed to whatever you want too:

background-color: #000;