function popct(url, w, h) {
var flist = ',location=0,directories=0,resizable=0,status=0,toolbar=0,menubar=0,scrollbars=1';
var popw = (screen.width - w) / 2;
var poph = (screen.height - h) / 2;
var popft = 'height=' + h + ',width=' + w + ',top=' + poph + ',left=' + popw + flist;
window.open(url, 'window', popft);
}