Popup Center

// The name is just an identifier for the window. It won't be used as a title for the window.
// It also must not contain white spaces. Although most of the browsers ignore space, IE fires an exception.

function popupCenter(pageURL, name, w, h) {
   var left = (screen.width / 2) - (w / 2);
   var top = (screen.height / 2) - (h / 2);
   var targetWin = window.open(pageURL, name, 'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, copyhistory=no, width=' + w + ', height=' + h + ', top=' + top + ', left=' + left);
}