mootools fx.reveal

Question

I'm trying to do a simple show/hide transition for a message div using fx.reveal in mootools 1.4. The effect works the first time, but not on subsequent clicks.

Any hints as to where I'm going wrong?

http://jsfiddle.net/MYgH6/1/

var mytween = new Fx.Reveal(document.getElementById('mydiv'), {duration: 2500});

$('myclick').addEvent('click', function(){
    mymessage();
});

function mymessage(){
    var mymessage = document.getElementById('mydiv');

    mymessage.set('html','YO!');

    mytween.reveal();
    mytween.dissolve();
}

Answer 1

var mytween = new Fx.Reveal(document.getElementById('mydiv'), {
    duration: 1000,
    onComplete:function(){
        this.element.dissolve();
    }
});

$('myclick').addEvent('click', function(){
    mymessage();
});

function mymessage(){
    var mymessage = document.getElementById('mydiv');

    mymessage.set('html','YO!');

    mytween.reveal();
}