function preload_images(){
  k = new Image();	
  k.src = 'img/arrow1_over.gif';
  l = new Image();	
  l.src = 'img/label_1_a.gif';
  m = new Image();	
  m.src = 'img/label_2_a.gif';
}
preload_images();
function winOpener(URLL, W, H)
{
var w=window.screen.width; 
var h=window.screen.height;
var X=Math.ceil((w-W)/2);
var Y=Math.ceil((h-H)/2);
var WinID="win"+Math.round(Math.random()*10000);
var CWIN=window.open(
URLL,
WinID,
"top="+Y+", left="+X+",width="+W+",height="+H+
",scrollbars=0,status=0,menubar=0,resizable=0");
}