S1：new操作符

function Shape(type){
    this.type = type || "rect";
    this.calc = function(){
        return "calc, "+this.type;
    }
}
var triangle = new Shape("triangle");
print(triangle.calc());
var circle = new Shape("circle");
print(circle.calc());
//运行结果如下：
calc, triangle
calc, circle    

var triangle = new Shape("triangle");
//上一句相当于下面的代码
var triangle = {};
Shape.apply(triangle, ["triangle"]);