function Shape(name) {

　　this.id = Utils.getUID();

　　this.name = name;

}

Shape.prototype = {

　　destroy: function() {},

　　check: function() {}

}

function Circle() {

　　Shape.call(this, ‘circle‘);

}

Circle.prototype = Object.create(Shape.prototype);

Circle.prototype.draw = function() {}

js 继承