var _POPUP_FEATURES = 'location=0, statusbar=1, menubar=1, toolbar=1, scrollbars=1, resizable=1, width=1024, height=768';
function raw_popup(url, target, features) {
    if (isUndefined(features)) features = _POPUP_FEATURES;
    if (isUndefined(target  )) target   = '_blank';
    var theWindow = window.open(url, target, features);
    theWindow.focus();
    return theWindow;
}

function link_popup(src, features) {
    return raw_popup(src.getAttribute('href'), src.getAttribute('target') || '_blank', features);
}

function isUndefined(v) { 
    var undef;
    return v===undef;
}