How to use jquery-JS Tutorial-php.cn

Home

Web Front-end

JS Tutorial

How to use jquery

青灯夜游

Dec 05, 2018 pm 04:28 PM

jquery

How to use jquery: First load the jquery file through CDN loading or local loading of files; then execute the jQuery code through the jquery file.

How to use jquery

The operating environment of this article: Windows 7 system, Dell G3 computer, jquery version 3.2.1.

How to use jquery? This article will introduce to you what is jquery? Why use jquery? How to use jquery? Let everyone know how to use jquery, I hope it will be helpful to you.

What is jQuery?

jQuery is not a language, but it is well-written JavaScript code. It is a fast and concise JavaScript library that simplifies HTML document traversal, event handling, animation and Ajax Interactive for rapid web development.

Why choose jQuery?

jQuery is a very compact and well-written JavaScript code that improves developer productivity by writing very small amounts of code so that they can implement critical UI functionality.

The advantages of jQuery are:

1. There is no need to learn a new syntax to use jQuery, it is enough to understand simple JavaScript syntax.

2. The code is simple and clear, and complex functions can be implemented without writing multiple lines of code.

3. Helps improve application performance.

4. It helps develop web pages that are compatible with most browsers.

5. It helps to implement key UI-related functions without writing hundreds of lines of code.

How to use jQuery?

#1. Load the jQuery file

jQuery usually comes as a single JavaScript file that contains everything jQuery does out of the box. It can be included in a web page in the following ways:

1), load local jQuery file

First you need to

download the jQuery file to the local, jQuery JavaScript files can be downloaded from the jQuery official website, address: http://www.jquery.com.

Then load jQuery files

<script type="text/javascript" src="jQuery-1.4.1-min.js"></script>

2), load jQuery from CDN

What is CDN?

CDN stands for Content Distribution Network, also known as Content Delivery Network. It is a group of computers placed at various points connected to the replica network containing data files to maximize bandwidth. In a CDN, clients access a copy of the data closer to the client's location, rather than all clients accessing it from one specific server. This helps achieve better data retrieval performance on the client side.

There are two main CDNs available for hosting jQuery files:

a. Loading jQuery from the Microsoft AJAX CDN

Can be loaded from Microsoft AJAX CDN loads jQuery files. More details are available here. You need to keep the following markup in your page.

<script type="text/javascript" language="Javascript"  src="http://ajax.aspnetcdn.com/ajax/jquery/jquery-1.4.1.min.js"></script>

b. Loading jQuery from Google Libraries API

You can load jQuery files from Google CDN. You need to keep the following markup in your page.

<script type="text/javascript" language="Javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"> </script>

Benefits of loading jQuery from CDN:

1. Since there is no need to download the jQuery file, the page loads faster

2. Load jQuery files from the server, thus saving bandwidth

3. Scalable, usually CDNs place these files on servers located in different geographical locations around the world so that they load faster, so no matter where the user is browsing page, and your application will run normally.

Note:

Generally, loading jQuery from CDN and loading jQuery files from local area must be written in order to prevent loading jQuery files. CDN is not available. Therefore, you can write the following lines of code:

<!-- START - jQuery Reference -->
<script type="text/javascript" language="Javascript" 

    src="http://ajax.aspnetcdn.com/ajax/jquery/jquery-1.4.1.min.js"></script>
    <script type=&#39;text/javascript&#39;>//<![CDATA[
        if (typeof jQuery == &#39;undefined&#39;) {
            document.write(unescape("%3Cscript 
    src=&#39;/Script/jquery-1.4.1.min.js&#39; type=&#39;text/javascript&#39; %3E%3C/script%3E"));
}//]]>
</script>
<!-- END - jQuery Reference -->

2. Execute jQuery code

We may have two ways to execute jQuery code.

1. When the page loads, execute the jQuery code:

<script language="javascript" type="text/javascript">
$(function () {
$("#div1").css("border", "2px solid green");
});
</script>

or:

<script language="javascript" type="text/javascript">
$("#div1").css("border", "2px solid green");
</script>

The advantage of executing jQuery code in this way is that it will not wait The entire page loads completely, so you can use this if you want the user to see the effect as soon as the corresponding element loads.

But the disadvantage is that if the element that jQuery has to execute is not loaded, then it will error or you will not get the desired result; therefore, when using this way of executing jQuery code, you must make sure first Load the element where you want to use jQuery (you can put the jQuery code after the HTML element).

2. Only execute jQuery when the complete DOM object (complete page has been loaded). At this point the code must be wrapped in a .ready function.

<script language="javascript" type="text/javascript">
$(document).ready(function () {
$("#div1").css("border", "2px solid green");
});
</script>

这是执行jQuery的更好，更安全的方法。这样可以确保只有在浏览器中加载完整页面时才会执行jQuery代码，因此可以放心，用户不会在页面上看到任何不需要的行为。

总结：以上就是本篇文章的全部内容，希望能对大家的学习有所帮助。

The above is the detailed content of How to use jquery. 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

Python vs. JavaScript: The Learning Curve and Ease of UseApr 16, 2025 am 12:12 AM

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AM

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

From C/C to JavaScript: How It All WorksApr 14, 2025 am 12:05 AM

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

JavaScript Engines: Comparing ImplementationsApr 13, 2025 am 12:05 AM

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

Beyond the Browser: JavaScript in the Real WorldApr 12, 2025 am 12:06 AM

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.

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)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 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.

See all articles

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

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)

4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

R.E.P.O. Best Graphic Settings

4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Assassin's Creed Shadows: Seashell Riddle Solution

2 weeks agoByDDD

R.E.P.O. How to Fix Audio if You Can't Hear Anyone

4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

R.E.P.O. Chat Commands and How to Use Them

4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

VSCode Windows 64-bit Download

A free and powerful IDE editor launched by Microsoft

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software