JavaScript Object Property check, add, delete, and access operations _ javascript skills

This article describes how to check, add, delete, and access operation instances of JavaScript objects, this article provides code examples to explain how to add attributes to an object, check the existence of attributes, and delete and access attributes. For more information, see Check attributes

var mouse = { "name": "betta", "age": 3, "varieties": "milaoshu"} mouse.hasOwnProperty("name"); // truemouse.hasOwnProperty("sex"); //false

Add attribute

Define an object dog, then assign various features, then assign color features, and finally traverse all attributes and values

Var dog = {name: "Mango", type: "King of the Meeting", eat: function () {alert ("eat") ;}} Object. prototype. color = "white"; var name; for (name in dog) {document. write (name + "" + dog [name] +"
")}

The effect is as follows:

Name mango type club king eat function () {alert ("eat");} color white

Delete attributes

Var cat = {"name": "tom", "sex": "man", "color": "yellow"} delete cat. name; cat. sex = undefined; cat. color = null; alert ("whether the name attribute exists:" + cat. hasOwnProperty ("name"); // falsealert ("existence of sex property:" + cat. hasOwnProperty ("sex"); // truealert ("Whether the color attribute exists:" + cat. hasOwnProperty ("color"); // true

Access attributes

Var cat = {"name": "tom", "sex": "man", "color": "yellow"} var name1 = cat. name; // use the dot operator to access the object attribute var name2 = cat ["name"]; // use the brackets operator to access the object attribute

There are two ways to create an object

Var obj = new Object (); obj. name = "MangGuo"; obj. age = 25; var obj = {name: "MangGuo", // name is the property name, and "MangGuo" is the value age: 25}