window.addEvent('domready',function(){
    
    var el = $('paginas_web_bottom'),
    color = el.getStyle('background');
    $('paginas_web_bottom').addEvents({
        mouseenter: function(){
            this.morph({
                'background': '#000'
            });
        },
        mouseleave: function(){
            this.morph({
                'background': color
            });
        }
    });
    
});