function popupwindow(url, title, w, h) {
wLeft = window.screenLeft ? window.screenLeft : window.screenX;
wTop = window.screenTop ? window.screenTop : window.screenY;
var left = wLeft + (window.innerWidth / 2) - (w / 2);
var top = wTop + (window.innerHeight / 2) - (h / 2);
return window.open(url, title, 'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, copyhistory=no, width=' + w + ', height=' + h + ', top=' + top + ', left=' + left);
}
popupwindow('http://www.google.com/', 'hello', 400, 400);
