How jquery code is executed
$('#list > li').addClass('horiz')
If you put it here, it will be invalid if you write it like this. Why?
Because of this When the code is executed to the js script, the page in the body has not been rendered, and $('#list>li') cannot obtain the element
at all, so it must be executed after the page rendering is completed, and the DOM tree is generated. will be effective
So how can it be executed in the head? There are two methods:
1. Use the onload event of the window object: After the page element is loaded, call it again This js script (delayed call)
window.onload = function () {
$('#list > li').addClass('horiz')
}So is there a method with the same function in jquery? Of course there is, not only there is, but it is more efficient: ready()
$(document).ready(function () {
$('#list > li').addClass('horiz')
})Abbreviation:
$(function(){
//jq代码
$('#list > li').addClass('horiz')
})Of course, if you write the jquery code at the bottom of the html document, it will not be so troublesome, but it is still recommended to encapsulate the code with $(function(){})
Why is the $(document).ready() method more efficient than the window.onload event?
HTML page generation is divided into two steps:
1. Generate DOM tree: tell How many elements are there in the browser html file and the relationship between them
2. Load external resources: such as images, external files, etc.
The window.onload event must be When the dom tree is generated, the
$().ready() event can be triggered only after all external resources have been loaded: it can be triggered as long as the DOM is created, without waiting for all elements to be loaded, especially for larger pictures or file, the effect is very obvious
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>jquery代码的执行方式</title>
<style type="text/css">
.horiz {
float:left;
list-style: none;
margin: 10px;
}
</style>
<script type="text/javascript" src="../js/jquery-3.3.1.js"></script>
<script type="text/javascript">
$(function(){
//jq代码
$('#list > li').addClass('horiz')
})
</script>
</head>
<body>
<h2>购物清单</h2>
<ul id="list">
<li>生活用品
<ul>
<li><a href="">淘宝</a></li>
<li>箱包</li>
<li>衣服</li>
<li>鞋子</li>
</ul>
</li>
<li>数码产品
<ul>
<li><a href="">京东</a></li>
<li>笔记本电脑</li>
<li>显示器</li>
</ul>
</li>
<li>食品保健
<ul>
<li><a href="">拼多多</a></li>
<li>奶粉</li>
<a href="">玩具</a>
</ul>
</li>
</ul>
<!-- <script type="text/javascript" src="../js/jquery-3.3.1.js"></script> -->
<script type="text/javascript">
// $('#list > li').addClass('horiz')
// $(document).ready(function(){
// //这里放jQuery代码:将列表水平摆放
// $('#list > li').addClass('horiz')
// })
</script>
</body>
</html>The above is the detailed content of How jquery code is executed. For more information, please follow other related articles on the PHP Chinese website!
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
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
Replace String Characters in JavaScript
Mar 11, 2025 am 12:07 AM
Detailed explanation of JavaScript string replacement method and FAQ This article will explore two ways to replace string characters in JavaScript: internal JavaScript code and internal HTML for web pages. Replace string inside JavaScript code The most direct way is to use the replace() method: str = str.replace("find","replace"); This method replaces only the first match. To replace all matches, use a regular expression and add the global flag g: str = str.replace(/fi
8 Stunning jQuery Page Layout Plugins
Mar 06, 2025 am 12:48 AM
Leverage jQuery for Effortless Web Page Layouts: 8 Essential Plugins jQuery simplifies web page layout significantly. This article highlights eight powerful jQuery plugins that streamline the process, particularly useful for manual website creation
Build Your Own AJAX Web Applications
Mar 09, 2025 am 12:11 AM
So here you are, ready to learn all about this thing called AJAX. But, what exactly is it? The term AJAX refers to a loose grouping of technologies that are used to create dynamic, interactive web content. The term AJAX, originally coined by Jesse J
10 jQuery Fun and Games Plugins
Mar 08, 2025 am 12:42 AM
10 fun jQuery game plugins to make your website more attractive and enhance user stickiness! While Flash is still the best software for developing casual web games, jQuery can also create surprising effects, and while not comparable to pure action Flash games, in some cases you can also have unexpected fun in your browser. jQuery tic toe game The "Hello world" of game programming now has a jQuery version. Source code jQuery Crazy Word Composition Game This is a fill-in-the-blank game, and it can produce some weird results due to not knowing the context of the word. Source code jQuery mine sweeping game
How do I create and publish my own JavaScript libraries?
Mar 18, 2025 pm 03:12 PM
Article discusses creating, publishing, and maintaining JavaScript libraries, focusing on planning, development, testing, documentation, and promotion strategies.
jQuery Parallax Tutorial - Animated Header Background
Mar 08, 2025 am 12:39 AM
This tutorial demonstrates how to create a captivating parallax background effect using jQuery. We'll build a header banner with layered images that create a stunning visual depth. The updated plugin works with jQuery 1.6.4 and later. Download the
Load Box Content Dynamically using AJAX
Mar 06, 2025 am 01:07 AM
This tutorial demonstrates creating dynamic page boxes loaded via AJAX, enabling instant refresh without full page reloads. It leverages jQuery and JavaScript. Think of it as a custom Facebook-style content box loader. Key Concepts: AJAX and jQuery
How to Write a Cookie-less Session Library for JavaScript
Mar 06, 2025 am 01:18 AM
This JavaScript library leverages the window.name property to manage session data without relying on cookies. It offers a robust solution for storing and retrieving session variables across browsers. The library provides three core methods: Session
