function openPopupWindow(url,winname,myWidth,myHeight) {
//////////////////////////////////////////////////////
    var myLeft;
	var myTop;

	myLeft = (screen.availWidth-myWidth)/2;
	myTop = (screen.availHeight-myHeight)/2;

    WinAtts='toolbar=no,location=no,directories=no,status=yes,menubar=no,scrollbars=yes';
    WinAtts+=',resizable=yes,copyhistory=no,alwaysRaised=yes,width='+myWidth+',height='+myHeight;
    WinAtts+=',screenX='+myLeft+',screenY='+myTop+',left='+myLeft+',top='+myTop;
	
    window.open(url,winname,WinAtts);
}