// *************************************************
// open popup
// *************************************************
function open_popup(url)
{
    var xtop = (screen.height - 200) / 2;
    var xleft = (screen.width - 400) / 2;
    window.open(url,null,"top="+xtop+",left="+xleft+",height=200,width=400,status=no,toolbar=no,menubar=no,location=no,scrollbars=yes");
}

function open_popup(url,xwidth,xheight)
{
    var xtop = (screen.height - xheight) / 2;
    var xleft = (screen.width - xwidth) / 2;
    window.open(url,null,"top="+xtop+",left="+xleft+",height="+xheight+",width="+xwidth+",status=no,toolbar=no,menubar=no,location=no,scrollbars=yes");
}