


A brief analysis of JavaScript access object properties and methods and their differences_javascript skills
Attribute is a variable used to represent the characteristics of an object, such as color, size, weight, etc.; method is a function used to represent the operation of the object, such as running, breathing, jumping, etc.
In JavaScript, the "." operator is usually used to access the value of an object's properties. Or use [] as an associative array to access the properties of the object.
The properties and methods of an object are collectively called members of the object.
Accessing the properties of an object
In JavaScript, you can use "." and "[]" to access the properties of an object.
1. Use "." to access object properties
Syntax:
objectName.propertyName
Among them, objectName is the object name and propertyName is the property name.
2. Use "[ ]" to access object properties
Syntax:
objectName[propertyName]
Among them, objectName is the object name and propertyName is the property name.
Methods to access objects
In JavaScript, you can only use "." to access the methods of an object.
Syntax:
objectName.methodName()
Among them, objectName is the object name and methodName() is the function name.
[Example 5-1] Create a Person class:
function Person() { this.name=" 张三 "; // 定义一个属性 name this.sex=" 男 "; // 定义一个属性 sex this.age=22; // 定义一个属性 age this.say=function(){ // 定义一个方法 say() return "嗨!大家好,我的名字是 " + this.name + " ,性别是 " + this.sex + ",今年 " + this.age +"岁!"; } } var zhangsan=new Person(); alert("姓名:"+zhangsan.name); // 使用“.”来访问对象属性 alert("性别:"+zhangsan.sex); alert("年龄:"+zhangsan["age"]); // 使用“[ ]”来访问对象属性 alert(zhangsan.say); // 使用“.”来访问对象方法
PS: A brief analysis of the difference between the "." and "[]" methods of object access properties
In JavaScript, the "." operator is usually used to access the value of an object's properties. Or use [] as an associative array to access the properties of the object. But what is the difference between these two methods?
For example, read the property attribute value in object:
object.property
object['property']
Both of the above two methods can achieve attribute access.
1. Differences in grammar
The attribute name of the object in dot notation is an identifier, while the attribute name of the latter is a string.
2. The difference in flexibility
In JavaScript programming, you can create any number of properties for an object. But when using the "." operator to access the properties of an object, the property name is represented by an identifier. In a JavaScript program, identifiers must be entered literally; they are not a data type, so the program cannot operate on them. That is, identifiers are static and must be hardcoded in the program.
When using the array[] notation to access the attributes of an object, the attribute name is represented by a string. Strings are a JavaScript data type, so they can be manipulated and created while the program is running.
3. Performance differences
Array[] notation will perform expression operation when accessing attribute values. The dot representation directly accesses attribute values, and theoretically the execution efficiency will be higher than that of the array representation. Performance can actually be ignored.
Some scenarios must use array representation to dynamically access attribute values, which cannot be achieved with dot representation.
In general, there is not much difference between these two methods, and both have corresponding usage scenarios. Dot notation is generally used as a static object to access properties. The array representation is very useful when accessing attributes dynamically.

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics



Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...

There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.

JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.

How to merge array elements with the same ID into one object in JavaScript? When processing data, we often encounter the need to have the same ID...

In-depth discussion of the root causes of the difference in console.log output. This article will analyze the differences in the output results of console.log function in a piece of code and explain the reasons behind it. �...

Discussion on the realization of parallax scrolling and element animation effects in this article will explore how to achieve similar to Shiseido official website (https://www.shiseido.co.jp/sb/wonderland/)...

Learning JavaScript is not difficult, but it is challenging. 1) Understand basic concepts such as variables, data types, functions, etc. 2) Master asynchronous programming and implement it through event loops. 3) Use DOM operations and Promise to handle asynchronous requests. 4) Avoid common mistakes and use debugging techniques. 5) Optimize performance and follow best practices.

Explore the implementation of panel drag and drop adjustment function similar to VSCode in the front-end. In front-end development, how to implement VSCode similar to VSCode...
