function fade(start, end, duration, element, easing, callback)
    {
        YAHOO.util.Dom.setStyle(element, 'opacity', start);
        var animation = new YAHOO.util.Anim(
            element,
            { opacity: {to: end} },
            duration,
            easing
        );
        if (callback) { animation.onComplete.subscribe( callback ); }
        animation.animate();
    }

/* This is dirty and somewhat brittle... */
function popupClose() { show_popup('popupmessage'); }