Check properties
var mouse = { "name": "betta", "age": 3, "varieties": "milaoshu" } mouse.hasOwnProperty("name"); // true mouse.hasOwnProperty("sex"); //false
Add attributes
Define an object dog, then assign various attributes, then assign the color attribute, and finally traverse all attributes and values
var dog={ name:"芒果", type:"会之王", eat:function(){ alert("吃"); } } Object.prototype.color="白色"; var name; for(name in dog){ document.write(name+" "+dog[name]+"<br>") }
The effect is as follows
name 芒果 type 会之王 eat function (){ alert("吃"); } color 白色
Delete attribute
var cat = { "name": "tom", "sex": "man", "color": "yellow" } delete cat.name; cat.sex = undefined; cat.color = null; alert("name属性是否存在:" + cat.hasOwnProperty("name")); //false alert("sex属性是否存在:" + cat.hasOwnProperty("sex")); //true alert("color属性是否存在:" + cat.hasOwnProperty("color")); //true
Access properties
var cat = { "name": "tom", "sex": "man", "color": "yellow" } var name1 = cat.name; //通过点操作符来访问对象属性 var name2 = cat["name"]; //通过中括号操作符来访问对象属性
There are two ways to create objects
var obj = new Object(); obj.name = "MangGuo"; obj.age = 25; var obj = { name : "MangGuo", //name是属性名,"MangGuo"是值 age : 25 }