/////////////////////////////////////////////////////////////////////
// Handle the background
/////////////////////////////////////////////////////////////////////

// This is really sneaky.  The darkening effect in the background of the frame
// is accomplished by having two images -- one normal and one that looks like a
// partly opaque black sheet was placed over the background.
//
// To make sure the background of the frame lines up with the background of the 
// main page, it's necessary to do some CSS work:
//
// BODY {
//    background-color: #000000;
//    background-image: url(menu_grey.jpg);
//    background-attachment: fixed;
//    background-position: -200px -100px;
// }
//
// or something similar.  This works for an iframe placed 200 pixels from the left
// and 100 from the top.
//
// I'm lazy, and I wanted to be free to explore new positioning schemes, so I 
// didn't want to hardcode the values in each sub-page.  This script "steals"
// the positioning information of its enclosing iframe in the main page and
// uses that to position the background appropriately.

var contentFrame = parent.document.getElementById('contentFrame');
if (contentFrame.style.left && contentFrame.style.top) {
  document.body.style.backgroundPosition = "-" + contentFrame.style.left + " -" + contentFrame.style.top;
}