原型模式

function Fn (){
this.x = 100;
this.y =200;
this.getX = function()
{
console.log(this.x)
        };
    }
Fn.prototype ={
constructor : Fn,
y:300,
getX ： function(){
console.log(this.x)
}
getY ： function(){
console.log(this.y)
    }
};
var f = new Fn;
f.getX();->100
f.prototype.getX();->undefined

Array.prototype.myUnique = function(){

var obj = {};
for(var i= 0;i<this.length;i++){
var cur = this[i];
if(obj[cur]===cur){
this[i] = this[this.length-1];
this.length--;
i--;
continue;
    }
obj[cur] = cur;

}
obj = null;
return this;//实现链式写法
}
var ary = [.......];
ary.myUnique（）.sort(function(a,b){return a-b})；