Object-oriented in JavaScript

1. What is object-oriented?

JS in everything is the object! The bottom of all objects is like a hash array.

In a program, an object is used to describe a specific thing in reality, so-called object-oriented is the instantiation of a class.

One thing in the real world contains properties and functions:

Attribute: A variable that describes a thing's characteristics, a value

Functions: Things can be done by the operation

What is an object: encapsulates storage space for multiple data and methods

What is a custom object: encapsulates the storage space for the properties and functions of a thing in reality.

The properties of something in reality become an attribute variable in the object.

The function of something in reality becomes a method (function) in the object

How to create an object:

1. Object Direct Amount       var obj={"Property name": value,        XXX: ...,               "method name":function() {...  This . Property name ...}               }

2. Use the New keyword       var obj=New// to Create an empty object      obj. property name = value;      Obj. method name =function() {... this. Property name ...}

3. Create * Same structure * with constructor * repeating *object: constructor: A special function that describes a class of object Structures 2 steps:1. Defining Constructorsfunctionsumname (value1,.....) {              This. property name =attribute parameter 1; //adds a property name to the object that is currently being created         //value assigned to attribute parameter 1             ...              This. Method name =function(){                  ... This. Property name ...} }      2To create an object with a constructor:varobj=NewSumname (value1,...);

2. What are the characteristics of object-oriented?

Object-oriented three main features: encapsulation inheritance polymorphism

Encapsulation: A property and method that describes the same thing, defined in an object

Inheritance: Properties and methods in the parent object that can be used directly by the child object

Polymorphic: The same object, which renders different states in different situations

Note: Overloads--the same method name, incoming parameters differ, perform different actions

Overriding: A child object feels that a member of the parent object is not good to use and can define itself to overwrite the members of the parent object

Object-oriented in JavaScript