function PopUp(ref)
{	
	var strFeatures="toolbar=no,status=no,menubar=no,location=no"
	strFeatures=strFeatures+",scrollbars=yes,resizable=yes,height=625,width=850"
	
	newWin = window.open(ref,"TellObj",strFeatures);
       newWin.opener = top;
}
<!-- =========================================================================-->
var plain_window = null;

function fWindow(destination,destname){

  if(screen.availWidth){
                if(screen.availWidth > 650){
                var wdt = 770;
                var hgt = 470;}
                else{
                var wdt = 610;
                var hgt = 460;}}
  else{
                var wdt = 610;
                var hgt = 460;}

  var specials = "width=" + wdt + ",height=" + hgt + ",top=0,left=0,toolbar,resizable,scrollbars,menubar";
  plain_window = window.open(destination,destname,specials);
  plain_window.focus();
  }