JavaScript basics-Object-oriented programming <2>

2. Dynamically add, modify, and delete object properties and methods

For example: Create an empty object user with Class object () and modify its behavior.

(1) Adding attributes

var user=New// Create an empty object with no properties and methods // Add property name//  Add attributeage user.sex= "Male"

If the result is output, a statement such as alert (User.Name) can be displayed.

(2) Add method

For the previous empty object user, add a Method alert ():

user.alert=function() {        alert ("My name is:" +this. name);  }

Call: User.alert (); can display its name as Jack

(3) Modifying properties and methods

The modification is to replace the old property with the new attribute.

For example:

User.name= "Tom"; User.alert=function() {      alert ("Hello," +this// in this method, the Name property hasalready been replaced by Tom}

If you use the popup dialog box to display its contents, the User.alert () value is "Hello,tom".

(4) deleting properties and methods

In fact, deleting a property or method is defining its value as undefined, which is

User.name=Undefined;user.alert=undefined;

3. Creating untyped objects using curly brace syntax

Its syntax is:

{    property1:statement,    property2:statement,    ...,    propertyn:statementn}

Here, you implement the definition of an object by using braces to make multiple properties or methods a group.

Example: Creating an object with curly brace syntax

<script language= "javascript" type= "Text/javascript" >varobj={};//defines an empty object, equivalent to the Var obj=new object ();   varUser={name:"Jack,"//define the Name property and assign the initial valuefavoritecolor:["Red", "green", "black"],//defining a color arrayHellofunction(){//Defining MethodsAlert ("Hello" + This. Name); }, Sex:"Male"} user.hello (); //Calling Methods</script>

4.prototype objects

Each function is actually an object, and their corresponding class is function. They have a special identity, and each function object has a sub-object prototype, which means that prototype represents the prototype of the function. and the function is

Class, prototype is a collection of members that represents a class.

Since Protoype is an object, it is also possible to modify its properties and methods dynamically

For example:

function Class1 () {     / / null function }class1.protoype.method=function// Add Method                     alert ("It ' s a text method");}     var obj1 =new  Class1 ();     // Calling Object Methods

JavaScript basics-Object-oriented programming <2>