prototype的实质
<script>
var p=function()
{
this.name="defaultname";
};
p.prototype.MyName=function()
{
alert(this.name);
}
var c=function()
{
}
c.prototype=new p();
==>c.prototype={name:"defaultname",Mynane:function(){alert(this.name);}}
==>c.prototype.name="defualtyname";
c.prototype.Myname=function(){alert(this.name);};
c.prototype.constructor=function(){this.name="defaultname";};
c.prototype.constructor();
var pp=new p();
alert(pp.aa);
//类的prototype实际上是一个类的实例,即是一个对象,又因为对象的属性可以动态的扩展,
//所以,c.prototype.b="";c.prototype["b"]="";等操作
</script>