addClass和removeClass函数

  function addClass1(element,value){

        if(!element.className){

            element.className = value;

        }else{

            newClassName = element.className;

            newClassName += " ";

            newClassName += value;

            element.className =newClassName;

        };

    };

    function addClass2(ele,className){

        ele.className += " " + className;

    };

    function addClass3(node,className){

        return node.className += " " + className;

    };

　　

   function removeClass2(ele,className){

        var tmpClassName = ele.className;

        ele.className = null;

        ele.className = tmpClassName.split(new RegExp(" " + className + "|" + className + " " + "|" + "^" + className + "$","ig")).join("");

    };

    function removeClass3(node,className){

        eles = node.className.split(/\s+/);//先将已有的class放进数组

        for(var i = 0; i < eles.length; i++){

            if(eles[i] == className){

                eles.splice(i,1);//再遍历删除指定的class

            };

        };

        node.className = eles.join("");//最后将新的数组用空格隔开重新添加回className

        return node;

    };