IE4 = (window.document.all) ? 1 : 0;
NS6 = (window.document.getElementById) ? 1 : 0;
NS4 = (window.document.layers) ? 1 : 0;
if (IE4)
  {
    screenHeight = document.body.clientHeight;
  }
else if (NS6)
  {
    screenHeight = window.innerHeight + 5;		
  }
else if (NS4)
  {
    screenHeight = window.innerHeight + 8;
  }
obj_height = screenHeight - 240;