function open_url(url,w,h){
  var left = Math.abs((w - screen.width) / 2);
  var top = Math.abs((h - screen.height) / 2);

  window.open(url,"popup","width="+w+",height="+h+",left="+left+",top="+top+",scrollbars=yes");	
  
//  hide_divs();
}