search
HomeWeb Front-endJS TutorialHow to use jquery efficiently

As a programmer, you will definitely use jQuery and javascript. So if we want to develop a good program, how can we use jQuery and javascript more efficiently to improve your jQuery and javascript code? Good code will bring speed improvements, and fast rendering and response mean a better user experience. So the content of this section is to bring you the efficient use of jQuery and javascript.

First of all, keep in mind that jQuery is javascript. This means we should adopt the same coding conventions, style guides and best practices.

First of all, if you are a javascript novice, I recommend you read "24 JavaScript Best Practices for Beginners". This is a high-quality javascript tutorial. It is best to read it before contacting jQuery.

When you are ready to use jQuery, I strongly recommend that you follow these guidelines:

1. Cache variables

DOM traversal is expensive, so try to reuse elements cache.

//糟糕h=$('#element').height();$('#element').css('height',h-20);
//建议$element=$('#element');h=$element.height();$element.css('height',h-20);

2. Avoid global variables

jQuery As with javascript, in general, it’s best to make sure your variables are within function scope.

//糟糕$element=$('#element');h=$element.height();$element.css('height',h-20);
//建议var $element=$('#element');var h=$element.height();$element.css('height',h-20);

3. Use Hungarian nomenclature

Add $ prefix before the variable to easily identify the jQuery object.

//糟糕
var first=$('#first');
var second=$('#second');
var value=$first.val();
// 建议 - 在 jQuery 对象前加 $ 前缀    
var $first=$('#first');
var $second=$('#second'),
var value=$first.val();

4. Use var chain (single var mode)

Combine multiple var statements into one statement. I recommend putting unassigned variables at the end.

var 
  $first=$('#first'),
  $second=$('#second'),
  value=$first.val(),
  k=3,
  cookiestring='SOMECOOKIESPLEASE',
  i,
  j,
  myArray={};

5. Please use 'on'

In the new version of jQuery, the shorter on("click") is used to replace functions like click(). In previous versions on() was bind(). Since jQuery 1.7, on() is the preferred method for attaching event handlers. However, for consistency's sake, you can simply use the on() method all together.

//糟糕$first.click(function(){    $first.css('border','1px solid red');    $first.css('color','blue');});
$first.hover(function(){    $first.css('border','1px solid red');})
// 建议$first.on('click',function(){    $first.css('border','1px solid red');    $first.css('color','blue');})
$first.on('hover',function(){    $first.css('border','1px solid red');})

6. Simplify javascript

Generally speaking, it is best to combine functions as much as possible.

//糟糕$first.click(function(){    $first.css('border','1px solid red');    $first.css('color','blue');});
//建议$first.on('click',function(){    $first.css({        'border':'1px solid red',        'color':'blue'    });});

7. Chained operations

jQuery It is very easy to implement chained operations of methods. Take advantage of this below.

//糟糕$second.html(value);$second.on('click',function()
{    alert('hello everybody');});$second.fadeIn('slow');$second.animate({height:'120px'},500);
//建议$second.html(value);$second.on('click',function()
{    alert('hello everybody');}).fadeIn('slow').animate({height:'120px'},500);

8. Maintain the readability of the code

Along with streamlining the code and using chaining, it may make the code difficult to read. Adding pinches and line breaks can work wonders.

//糟糕$second.html(value);$second.on('click',function()
{    alert('hello everybody');}).fadeIn('slow').animate({height:'120px'},500);
//建议$second.html(value);$second    .on('click',function(){ alert('hello everybody');})    .fadeIn('slow')    .animate({height:'120px'},500);


9. Select short-circuit evaluation

Short-circuit evaluation is an expression that is evaluated from left to right, using && (logical AND) or || ( Logical OR) operator.

//糟糕function initVar($myVar) {    if(!$myVar) {        $myVar=$('#selector');    }}
//建议function initVar($myVar) {    $myVar=$myVar || $('#selector');}

10. Choose shortcuts

One way to streamline your code is to take advantage of coding shortcuts.

//糟糕if(collection.length > 0){..}
//建议if(collection.length){..}

11. Separate elements during heavy operations

If you plan to do a lot of operations on DOM elements (setting multiple attributes or css styles in succession), it is recommended to separate the elements first and then add them.

//糟糕var     $container=$("#container"),    $containerLi=$("#container li"),    $element=null;
$element=$containerLi.first(); //... 许多复杂的操作
//建议var     $container=$("#container"),    $containerLi=$container.find("li"),    $element=null;
$element=$containerLi.first().detach(); //... 许多复杂的操作
$container.append($element);

12. Memorize Tips

You may be inexperienced with using methods in jQuery, be sure to check the documentation, there may be a better or faster way to use it.

//糟糕$('#id').data(key,value);
// 建议 (高效)  $.data('#id',key,value);

13. Cache parent elements using subqueries

As mentioned earlier, DOM traversal is an expensive operation. A typical approach is to cache parent elements and reuse these cached elements when selecting child elements.

//糟糕var     $container=$('#container'),    $containerLi=$('#container li'),    $containerLiSpan=$('#container li span');
// 建议 (高效)  var     $container=$('#container '),    $containerLi=$container.find('li'),    $containerLiSpan= $containerLi.find('span');


14. Avoid universal selectors

Putting universal selectors into descendant selectors has very poor performance.

//糟糕$('.container > *');
//建议$('.container').children();

15. Avoid implicit universal selectors

Universal selectors are sometimes implicit and difficult to find.

//糟糕$('.someclass :radio');
//建议$('.someclass input:radio');

16. Optimize selectors

For example, the id selector should be unique, so there is no need to add additional selectors.

//糟糕$('div#myid'); $('div#footer a.myLink');
// 建议$('#myid');$('#footer .myLink');

17. Avoid multiple ID selectors

I emphasize here that the ID selector should be unique, there is no need to add additional selectors, and there is no need for multiple descendant ID selectors. .

//糟糕$('#outer #inner');
//建议$('#inner');

18. Stick to the latest version

Newer versions are usually better: lighter weight, more efficient. Obviously, you need to consider the compatibility of the code you want to support. For example, version 2.0 does not support Internet Explorer 6/7/8.

19. Abandon deprecated methods

It is very important to pay attention to the deprecated methods in each new version and try to avoid using these methods.

//糟糕- live 已经废弃   $('#stuff').live('click',function() {  console.log('hooray');});
// 建议$('#stuff').on('click',function() {  console.log('hooray');});
// 注:此处可能不当,应为live能实现实时绑定,delegate或许更合适

20. Using CDN

Google's CND can ensure that the cache closest to the user is selected and responds quickly. (Please search the address yourself when using Google CND. The address here cannot be used. We recommend the CDN provided by jquery official website).

21. Combine jQuery and javascript native code when necessary

As mentioned above, jQuery is javascript, which means that anything you can do with jQuery can also be done with native code. Native code (or vanilla) may be less readable and maintainable than jQuery, and the code is longer. But it also means more efficient (usually the closer to the underlying code the less readable the higher the performance, for example: assembly, which of course requires more powerful people). Keep in mind that no framework can be smaller, lighter, and more efficient than native code (note: the test link is no longer valid, you can search for the test code online).

Given the performance differences between vanilla and jQuery, I strongly recommend taking the best of both and using (if possible) native code equivalent to jQuery.

The purpose of this article is to improve the performance of jQuery and some other good suggestions. If you want to delve deeper into this topic you will find a lot of fun. Remember, jQuery is not required, just an option. Think about why you want to use it. DOM manipulation? ajax? stencil? css animation? Or a selector engine? Perhaps a javascript microframework or a custom version of jQuery would be a better choice.

The above is how to use jQuery and javascript efficiently. After reading this article, I hope it will be helpful to everyone's development.

Related recommendations:

What is the difference between JS and JQUERY

The method tied to $,jQuery in the jq source code

jQuery form validation example code

The above is the detailed content of How to use jquery efficiently. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Building a Multi-Tenant SaaS Application with Next.js (Backend Integration)Building a Multi-Tenant SaaS Application with Next.js (Backend Integration)Apr 11, 2025 am 08:23 AM

I built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing

How to Build a Multi-Tenant SaaS Application with Next.js (Frontend Integration)How to Build a Multi-Tenant SaaS Application with Next.js (Frontend Integration)Apr 11, 2025 am 08:22 AM

This article demonstrates frontend integration with a backend secured by Permit, building a functional EdTech SaaS application using Next.js. The frontend fetches user permissions to control UI visibility and ensures API requests adhere to role-base

JavaScript: Exploring the Versatility of a Web LanguageJavaScript: Exploring the Versatility of a Web LanguageApr 11, 2025 am 12:01 AM

JavaScript is the core language of modern web development and is widely used for its diversity and flexibility. 1) Front-end development: build dynamic web pages and single-page applications through DOM operations and modern frameworks (such as React, Vue.js, Angular). 2) Server-side development: Node.js uses a non-blocking I/O model to handle high concurrency and real-time applications. 3) Mobile and desktop application development: cross-platform development is realized through ReactNative and Electron to improve development efficiency.

The Evolution of JavaScript: Current Trends and Future ProspectsThe Evolution of JavaScript: Current Trends and Future ProspectsApr 10, 2025 am 09:33 AM

The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.

Demystifying JavaScript: What It Does and Why It MattersDemystifying JavaScript: What It Does and Why It MattersApr 09, 2025 am 12:07 AM

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.

Is Python or JavaScript better?Is Python or JavaScript better?Apr 06, 2025 am 12:14 AM

Python is more suitable for data science and machine learning, while JavaScript is more suitable for front-end and full-stack development. 1. Python is known for its concise syntax and rich library ecosystem, and is suitable for data analysis and web development. 2. JavaScript is the core of front-end development. Node.js supports server-side programming and is suitable for full-stack development.

How do I install JavaScript?How do I install JavaScript?Apr 05, 2025 am 12:16 AM

JavaScript does not require installation because it is already built into modern browsers. You just need a text editor and a browser to get started. 1) In the browser environment, run it by embedding the HTML file through tags. 2) In the Node.js environment, after downloading and installing Node.js, run the JavaScript file through the command line.

How to send notifications before a task starts in Quartz?How to send notifications before a task starts in Quartz?Apr 04, 2025 pm 09:24 PM

How to send task notifications in Quartz In advance When using the Quartz timer to schedule a task, the execution time of the task is set by the cron expression. Now...

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. How to Fix Audio if You Can't Hear Anyone
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
WWE 2K25: How To Unlock Everything In MyRise
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools