擼一遍繼承

function aa(x){
    this.x=x;
    this.sayx=function(){
        console.log(x);
    }
}
aa.prototype = {
    do:function(){
        console.log("嘟嘟")
    }
}
function bb(y,x){
    this.y=y;
    aa.call(this,x);
}
//bb.prototype = Object.create(aa);
bb.prototype = Object.create(aa.prototype);
//bb.prototype = aa.prototype;
//bb.prototype = new aa();
/*割了*/
//var f = funciton(){};
//f.prototype = aa.prototype;//或者new
//bb.prototype = new f();
//bb.prototype = new aa("ccc");
bb.prototype.do1=function(){
    console.log("嘟嘟1");
}
bb.prototype.constructor=bb;
var cc = new bb("aa","bb");
console.dir(cc);

總之一句話，原型鏈就是把一個對象鏈接到另外一個對象到另外一個對象....
對prototype賦值對象會破壞構造函數，prototype.dosthing這樣能夠避免掉。
prototype.proto