function popup(url,_w,_h) {
            var w=_w;
            var h=_h;
            var scroll='no';
            var winl = (screen.width-w)/2;
            var wint = ((screen.height-h)/2)-30;
            var settings  ='height='+h+',';
            settings +='width='+w+',';
            settings +='top='+wint+',';
            settings +='left='+winl+',';
            settings +='scrollbars=yes,';
            settings +='resizable=no,';
            settings +='menubar=0,status=0';
            win=window.open(url,"popup",settings);
            if(parseInt(navigator.appVersion) >= 4){win.window.focus();}
}