I am using this JavaScript code to remove a couple elements from the page, but it's not working. When I inspect the code with Opera Dragonfly it says something like:

Uncaught exception: Error: WRONG_ARGUMENTS_ERR

and points to the file and function name.

The weird thing is that I use the exact same code in another function on the same page and it works without problem. The code is very small and simple:

var docBody = document.getElementById(body);

if(document.getElementById(marginDiv)){

  docBody.removeChild(marginDiv);

}

Both body and marginDiv exist on the page. My goal is to make the thumbnails disappear when one clicks the background.