初学Javascript对象

<script>
    var p=new Object();
 
    //属性
    p.width=;
    p.height=;
    p.num=;
    p.autotime=;
 
    //方法
    p.autoplay=function(){
        alert("play....");
    }
    p.test=function(){
 
    }
 
alert(p.width);
 
p.autoplay();
</script>

    var test = {
 
        alr:function(){
            var Oul = document.getElementById('ul');
            var Oli = Oul.getElementsByTagName('li');
            for(var i=;i<Oli.length;i++){
 
                (function(i){
                    Oli[i].onclick=function(){
                        alert(i)
                    }
                })(i);
            }
        }
    }
 
    test.alr();

    function test(){
 
        this.alr=function(){
            var Oul = document.getElementById('ul');
            var Oli = Oul.getElementsByTagName('li');
            for(var i=;i<Oli.length;i++){
 
                (function(i){
                    Oli[i].onclick=function(){
                        alert(i)
                    }
                })(i);
            }
        }
    }
 
    var Ojc = new test();
 
    Ojc.alr();

    //创建原型对象，定义属性、方法、及对象事件等。
    Student.prototype={
        _name:null,
        _age:null,
        _sex:null,
        ShowName:function()
        {
            alert("Name:"+ this._name +"\n" + "Age:" + this._age + "\n" + "Sex:"+ this._sex);
        }
    }
 
    //专门用一个函数来初始化对象。
    function Student(name,age,sex)
    {
        this._name=name;
        this._age=age;
        this._sex=sex;
    }
 
    var student = new Student("小明",,"男"); //实例化
    student.ShowName(); //调用对象方法 

    var  lp = {
       name:    "Vicky",
       age:     ,
       eat: function() {
              alert('1');
       },
       sleep: function() {
           alert('2');
        }
    };
 
    lp.sleep();

    var index =
    function A(x,y) {
        this.x = x;
        this.y = y;
        A.prototype.FunX = function(){
            document.body.style.background = 'red';
        };
        A.prototype.FunY = function(){
            alert(y)
        };
    }
 
    var obj = new A(,);
    alert(obj.x);
    alert(obj.y);
    obj.FunX();
    obj.FunY();