function ShowShadowMenu(el, color, depth)
   {
      //draw a series of cascading rectangles to create shadow
      for (var i = depth; i > 0; i--)
      {
         var rect = document.createElement('div');
         var rs = rect.style
         rs.position = 'absolute';
   
         rs.left = (el.offsetLeft + i) + 'px';
         rs.top = (el.offsetTop + i) + 'px';

         rs.width = el.offsetWidth + 'px';
         rs.height = el.offsetHeight + 'px';
   
         //put rectangle behind the table
         rs.zIndex = el.style.zIndex - i;
         rs.backgroundColor = color;
   
         //make the shadow transparent
         var opacity = 1 - i / (i + 1);
         rs.filter = 'alpha(opacity=' + (100 * opacity) + ')';
   
         //add shadow to document
         el.insertAdjacentElement('afterEnd', rect);

      }
   }