原声js实现addClass removeClass toggleClass效果

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>

<body>
        <div id = "test" style = "width:250px;height:100px;">  
            sssssssssssss  
        </div>  
        <input type = "button" value = "toggleClassTest" onclick = "toggleClassTest();" />  
    </body>
</html>
    <style type="text/css">  
        div.testClass{  
            background-color:gray;  
        }  
    </style>  
      
    <script type="text/javascript">  
    function hasClass(obj, cls) {  
        return obj.className.match(new RegExp('(\\s|^)' + cls + '(\\s|$)'));  
    }  
      
    function addClass(obj, cls) {  
        if (!this.hasClass(obj, cls)) obj.className += " " + cls;  
    }  
      
    function removeClass(obj, cls) {  
        if (hasClass(obj, cls)) {  
            var reg = new RegExp('(\\s|^)' + cls + '(\\s|$)');  
            obj.className = obj.className.replace(reg, ' ');  
        }  
    }  
      
    function toggleClass(obj,cls){  
        if(hasClass(obj,cls)){  
            removeClass(obj, cls);  
        }else{  
            addClass(obj, cls);  
        }  
    }  
      
    function toggleClassTest(){  
        var obj = document. getElementById('test');  
        toggleClass(obj,"testClass");  
    }  
    </script>