(function() {
            var attributes1 = {
                height: { to: 100, unit: 'px' }
            };
            var attributes2 = {
                height: { to: 0, unit: 'px'}
            };
            var anim1 = new YAHOO.util.Anim('login', attributes1, 0.3);
            var anim2 = new YAHOO.util.Anim('login', attributes2, 0.3);
            var box = document.getElementById('login');
            YAHOO.util.Event.on('btnlogin', 'click', function() {
                if(box.className == "shown") {
                    anim2.animate();
                    box.className = "hidden";
                } else {
                    anim1.animate();
                    box.className = "shown";
                }
            });
        })();