function Popup(url, window_name, window_width, window_height) {
    settings=
    "toolbar=no,location=no,directories=no,"+
    "status=no,menubar=no,scrollbars=yes,"+
    "resizable=yes,width="+window_width+",height="+window_height;
    NewWindow=window.open(url,window_name,settings);
}