chrome24+, firesfox26+起支持classList2.0,即让它同时添加或删除多个类名, toggle方法支持第2个参数，用于强制添加或删除

var div = document.createElement("div");div.classList.add("a", "b");if (div.className !== "a b" && window.DOMTokenList) {    var _add = DOMTokenList.prototype.add;    DOMTokenList.prototype.add = function() {        for (var i in arguments) {            _add.call(this, arguments[i]);        }    };    var _remove = DOMTokenList.prototype.remove;    DOMTokenList.prototype.remove = function() {        for (var i in arguments) {            _remove.call(this, arguments[i]);        }    };    DOMTokenList.prototype.toggle = function(token, forse) {        token += "";        var                result = this.contains(token) , method = result ?                forse !== true && "remove"  : forse !== false && "add";        if (method) {            this[method](token);        }        return !result;    };}

 

div.className =

"";

div.classList.add(

"aaa"

,

"ccc"

);

alert(div.className);