JS当中，获取原型的三种方式和两种原型的使用方法

获取原型的三种方法

function R(){
	}
	var one=new R();
	console.log(Object.getPrototypeOf(one));	//官方推荐，规范写法
	console.log(one.proto);						//不报错，不推荐
	console.log(one.constructor.proto)	//同上

a.通过给既定对象的属性赋值

var Calculator = function (para1, para2) {
	        this.para1 = para1;
	        this.para2 = para2;
   		 };
   		 Calculator.prototype = {
	        add: function (para1, para2) {
	            return para1 + para2;
	        },
	        sub: function (para1, para2) {
	            return para1 - para2;
	        }
  		 };
    var c = new Calculator();

b.在赋值原型prototype的时候使用function立即执行的表达式来赋值。格
式为xx.prototype = function(){ }();

 	var Calculator = function (para1, para2) {
        this.para1 = para1;
        this.para2 = para2;
    };
     Calculator.prototype = function(){
        add = function (para1, para2) {
            return para1 + para2;
        },
        sub = function (para1, para2) {
            return para1 - para2;
        }
        return {
            add:add,
            sub:sub
        }
    }();
   var c = new Calculator();