原生js实现toggle classname的功能

function hasClass(obj, cls) {  
    return obj.className.match(new RegExp('(\\s|^)' + cls + '(\\s|$)'));  
}  
  
function addClass(obj, cls) {  
    if (!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");  
}