javascript继承原型链继承

<script language="javascript" type="text/javascript">
    function Parent(){
    }
    function Child(){        
    }
    
    Parent.prototype.name="小张";
    Parent.prototype.sayHello=function (){
        alert(this.name);    
    }
    Child.prototype=Parent.prototype; /*等价于Child.prototype=new Parent();*/
    
    var ch=new Child();
    
    ch.sayHello();
</script>