Everything in JavaScript is an object: strings, numbers, arrays, dates, etc.
In JavaScript, an object is data with properties and methods.
JavaScript object is an unordered collection data type, which consists of several key-value pairs.
Object definition
You can use characters to define and create JavaScript objects:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
<script language="JavaScript">
var person = new Object();
person.name="kevin";
person.age=31;
alert(person.name);
alert(person["age"])
</script>
</head>
<body>
</body>
</html>
Object properties
It can be said that "JavaScript objects are containers of variables" .
However, we usually think of "JavaScript objects as containers of key-value pairs".
Key-value pairs are usually written as name : value (key and value are separated by colon).
Key-value pairs in JavaScript objects are often called object properties.
JavaScript objects are containers for property variables.
The object key-value pair is written similar to:
Associative array in PHP and Python Dictionary Hash table in C language Hash map in Java Hash table in Ruby and Perl
JavaScript objects are dynamically typed, and you can freely add or delete attributes to an object:
var xiaoming = {
name: '小明'
##};xiaoming.age; // undefined
xiaoming.age = 18; // Add an age attribute
##xiaoming.age; // 18
delete xiaoming .age; // Delete age attribute
##xiaoming.age; // undefined
delete xiaoming['name']; // Delete name attribute
xiaoming.name; // undefined
delete xiaoming.school; //Deleting a non-existent school attribute will not Error
Object methods
The method of an object defines a function and is stored as a property of the object.
Object methods are called (as a function) by adding ().
This instance accesses the fullName() method of the person object:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<p id="demo"></p>
<script>
var person = {
firstName: "Tom",
lastName : "Jay",
id : 666,
fullName : function()
{
return this.firstName + " and " + this.lastName;
}
};
document.getElementById("demo").innerHTML = person.fullName();
</script>
</body>
</html>Accessing object methods
You can create object methods using the following syntax:
methodName : function() { code lines }
You can access object methods using the following syntax:
objectName.methodName()
Usually fullName() is used as a method of the person object, and fullName is used as a property.
There are many ways to create, use and modify JavaScript objects.
There are also many ways to create, use and modify properties and methods.
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