jszs 对象引用

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script type="text/javascript">
window.onload = function ()
{
    var obj  = {
        a : { b : 10}
    };
    
    
    
    function copy(obj)//浅拷贝
    {
        var newObj = {};
        
        for(var attr in obj)
        {
            newObj[attr] = obj[attr]
        }
        return newObj;
    }
    
    
    function deepcopy(obj)
    {
        if(typeof obj != 'object')
        {
            return obj;
        }
        var newobj = {};
        
        for(var attr in obj)
        {
            newobj[attr] = deepcopy(obj[attr]);
        }
        return newobj;
    }
    
    var obj2 = deepcopy(obj);
    obj2.a.b = 50;
    
    alert(obj.a.b);
        
}
</script>
</head>

<body>
</body>
</html>