window.addEvent('domready', function() {

        var scroll = new Fx.Scroll(Window, {
            wait: false,
            duration: 800,
            offset: {'x': 0, 'y': 0},
            transition: Fx.Transitions.Quad.easeInOut
        });
         
        $('gotop').addEvent('click', function(event) {
            event = new Event(event).stop();
            scroll.toElement('bd');
        }); 

});