function WinOpen(url,winname,myWidth,myHeight) {
    var myLeft;
    var myTop;
    if( navigator.appName == "Microsoft Internet Explorer" ) {
      myHeight -= 100;
    } else if( navigator.appName == "Netscape" ) {
      myHeight -= 50;
    }
    myLeft = (screen.availWidth-myWidth)/2;
    myTop = (screen.availHeight-myHeight)/2;
    WinAtts='toolbar=no,location=no,directories=no,status=yes,menubar=yes,scrollbars=yes,resizable=yes,copyhistory=no,alwaysRaised=yes,width='+myWidth+',height='+myHeight+',screenX='+myLeft+',screenY='+myTop+',left='+myLeft+',top='+myTop;
    return window.open(url,winname,WinAtts);
}