case 2:
class_suffix = ‘-bottom’;
break;
case 3:
class_suffix = ‘-left’;
break;
}
obj.classList.add(state + class_suffix);
};
_nodes.forEach(function (el) {
el.addEventListener(‘mouseover’, function (ev) {
addClass(ev, this, ‘in’);
}, false);
el.addEventListener(‘mouseout’, function (ev) {
addClass(ev, this, ‘out’);
}, false);
});
原文:http://www.cnblogs.com/w2bc/p/5209690.html










