function goAway(item) {
    new Effect.toggle(item,'appear', {duration: 0.5});
}

var behaviours = {    

	'#flash' : function(div) {
	    var spans = div.getElementsByTagName('span');
	    var span = spans[spans.length-1]
        var actions = document.createElement('div');
        actions.className = 'flash_actions';
        actions.innerHTML = '<a href="#" title="Cerrar este mensaje" onclick="goAway(\'flash\'); return false;">¡Vete a tu caseta!</a>';
        span.appendChild(actions);
	}	
};

Behaviour.register(behaviours);