WEB前端开发社区 2021-07-23 1.1 什么是对象? var ball = new Object();ball.color = “red";ball.size = 12; 对象还有方法,方法用于定义对象的行为方式。 ball.roll = function() {return this.size * laps} 1.3 访问对象的属性 var ball = new Object();ball.color = “red";ball.size = 12;var spec = “color”;ball.spec ?? 这里假设有一个变量spec,我们需要通过这个变量spec来访问对象属性。 ball[spec]; // red 1.4 枚举对象的属性 var ball = {color: “red”, size: 12, border: 2};for (var prop in ball) {console.log(“ball.” + prop + “=“ + obj[prop]);}// ball.color = red// ball.size = 12// ball.border = 2// 如果希望继承的属性不显示,那么可以用hasOwnProperty函数来过滤一遍var bar = {a: 1, b: 2, c: 3};function Foo() {this.color = 'red';}Foo.prototype = bar;var obj = new Foo();for (var prop in obj) {if (obj.hasOwnProperty(prop)) {console.log(prop);}} 也可以通过Object.keys(obj)的方法来返回一个属性名集合的数组: var obj = {a: “123”, b: “das”, c: “web”};console.log(Object.keys(obj)); // [“a”,”b”,”c”];var arr = [“a”, “b”, “c”];console.log(Object.keys(arr)); // [“0”,”1”,”2”]; |
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