var pop = null;

function popup(obj,w,h) {
    var url = (obj.getAttribute) ? obj.getAttribute('href') : obj.href;
    if (!url) return true;

    w = (w) ? w += 20 : 150;  // 150px*150px is the default size
    h = (h) ? h += 25 : 150;
    var args = 'width='+w+',height='+h+',resizable,scrollbars=yes';
    pop = window.open(url,'',args);
    return (pop) ? false : true;
}