让IE10等支持classList2.0

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)