JavaScript Object properties Check, add, delete, access operation instances _javascript tips

Check Properties

var mouse = {
 "name": "Betta",
 "age": 3,
 "varieties": "Milaoshu"
}
 
Mouse.hasownproperty ("name"); True
mouse.hasownproperty ("sex");//false

Add properties

Defines an object dog, then assigns a variety of attributes, then gives the color attribute, and finally traverses all attributes and values

var dog={
 name: "Mango",
 type: "King of the Will",
 eat:function () {
  alert ("Eat");
 }
 object.prototype.color= "White";
 var name;
 for (name in dog) {
  document.write (name+ "" +dog[name]+ "<br>")
 }

The effect is as follows

Name Mango
type will King
eat function () {alert ("Eat");}
Color White

Delete attribute

var cat = {
  "name": "Tom",
  "sex": "Man",
  "color": "Yellow"
}
delete cat.name;
Cat.sex = undefined;
Cat.color = null;
Alert ("Name property exists:" + cat.hasownproperty ("name")); False
alert ("Sex property exists:" + cat.hasownproperty ("sex"));//true
alert ("Color property exists:" + cat.hasownproperty ( "Color")); True

Access Properties

var cat = {
  "name": "Tom",
  "sex": "Man",
  "color": "Yellow"
}
var name1 = cat.name;// Accessing object Properties
var name2 = cat["name" via the dot operator;//access to object properties through bracket operators

There are two ways to create objects

var obj = new Object ();
Obj.name = "Mangguo";
Obj.age =;

var obj = {
  name: "Mangguo",//name is the property name, "Mangguo" is the value
  age:25
}