给内置对象或自定义对象添加存取器属性(getter setter)的方法总结
funct = { get: function() { return this._x }, set: function(value) { this._x = value } } function Obj(){ this._x=0;} var obj1=new Obj; //Obj.prototype = { get x() { return this._x; }, set x(value) { this._x = value; }} //ok //Obj.prototype.__defineGetter__('x', funct['get']); //ok //Obj.prototype.__defineSetter__('x', funct['set']); Object.defineProperty(obj1, "x", { get: funct['get'], set: funct['set']}); //----- test ------- alert(obj1.x); //0 obj1.x = 100; alert(obj1.x); //100 //---- test end -----
~~~ Object.defineProperty() 给对象添加属性
Object.defineProperty(obj, "newDataProperty", {
value: 101,
writable: true,
enumerable: true,
configurable: true
});
通常我们添加属性只要 obj.attr=value 即可,Object.defineProperty()方法提供更多配置选项,可指定属性是否只读,是否可枚举 可配置