search
HomeWeb Front-endJS TutorialDetailed explanation of jQuery lazyload lazy loading

Lazy Load is a jQuery plug-in written in JavaScript. It can delay loading of images in long pages. Images outside the browser's visible area will not be loaded until the user scrolls the page to where they are. This is exactly the opposite of how image preloading is handled.

Lazy loading of images on long pages that contain many large images can speed up page loading. The browser will enter the ready state after loading the visible images. In some cases, it can also help reduce the load on the server.

Demo page:

Basic options

Fade-in effect

For browsers that do not support JavaScript Downgrade processing

Horizontal scrolling

Horizontal scrolling within the container

Vertical scrolling within the container

There are many N pictures in the page

After five years Load images after a delay of seconds

Use AJAX to load images

How to use

Lazy Load relies on jQuery. Please add the following code to the end of the HTML, that is < ;/body>Before:

<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="jquery.lazyload.js"></script>


You have to change the tag of the image. The address of the image must be placed on the data-original attribute. Give lazy loading images a specific class (for example: lazy). This way you can easily do image plugin bundling. The code is as follows:

<img class="lazy" alt="" width="640"    style="max-width:90%" data-original="img/example.jpg" />
$(function() {
 $("img.lazy").lazyload();
});


This will cause all images with class lazy to be loaded lazily.

Demo: Basic Options

TIPS: The width and height of the image must be set here, otherwise the plug-in may not work properly.

Set the threshold

By default, the image will be loaded when it appears on the screen. If you want to load the image in advance, you can set the threshold option. Set the threshold to 200 so that the image is 200 pixels away from the screen. Early loading.

$("img.lazy").lazyload({
 threshold : 200
});


Set events to trigger loading

You can use jQuery events such as click and mouseover. You can also use custom events, such as sporty and foobar. The default is to wait until the user scrolls down and the image appears in the viewport. Load images only when the user clicks on them:

$("img.lazy").lazyload({
 event : "click"
});


Demo: Load images after a five-second delay

Use special effects

By default, the plugin waits for the image to fully load and calls show(). You can use any effect you want. The code below uses fadeIn (fade in effect).

Demo: Fade in effect

$("img.lazy").lazyload({
 effect : "fadeIn"
});


For situations where JavaScript is not enabled

JavaScript for almost all browsers are all enabled. However, you may still want to display real images on clients that do not support JavaScript. To degrade gracefully when the browser does not support JavaScript, you can write the real image fragment in the

<img  class="lazy" data-original="img/example.jpg"    style="max-width:90%" heigh="480" alt="Detailed explanation of jQuery lazyload lazy loading" >
<noscript><img  src="img/example.jpg"    style="max-width:90%" heigh="480" alt="Detailed explanation of jQuery lazyload lazy loading" ></noscript>


##You can hide placeholders through CSS.

.lazy {
 display: none;
}


In browsers that support JavaScript, you must display the placeholder when the DOM is ready, which can be done at the same time as the plugin is initialized.

$("img.lazy").show().lazyload ();

Images in containers

You can use plug-ins on images in scrollable containers, such as DIV elements with scroll bars. All you have to do is define the container as jQuery The object is passed as a parameter to the initialization method.

Demo: horizontal scrolling in the container, vertical scrolling in the container

When the image is not continuous

When scrolling the page, Lazy Load will loop through the loaded images. During the loop, it is checked whether the image is within the visible area. By default, the loop stops when the first image that is not in the visible area is found. The image is considered to be distributed in a streaming manner, and the image is in the page The order is the same as that in HTML code. But in some layouts, this assumption is not true. However, you can control the loading behavior through the failurelimit option.

$("img.lazy").lazyload({
 failure_limit : 10
});


Set failurelimit to 10, so that the plug-in will stop searching only when it finds 10 images that are not in the visible area. If you have a cumbersome layout, please set this parameter higher.

Loading Hide There may be many hidden pictures buried on your page. For example, if the plug-in is used to filter the list, you can constantly modify the display status of each item in the list. In order to improve performance, Lazy Load defaults Hidden images are ignored. If you want to load hidden images, please set skip_invisible to false

$("img.lazy").lazyload({
 skip_invisible : false
});

Download plugin

Latest version source code and compressed code. The plug-in is already available on OSX’s Safari 5.1, Safari 6, Chrome 20, Firefox 12 browsers, Windows’ Chrome 20, IE 8 and IE 9 browsers, and iOS5 (iPhone and Tested on Safari 5.1 browser of iPad).


For more detailed explanations of jQuery lazyload, please pay attention to the PHP Chinese website for articles related to lazy loading!

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
Node.js Streams with TypeScriptNode.js Streams with TypeScriptApr 30, 2025 am 08:22 AM

Node.js excels at efficient I/O, largely thanks to streams. Streams process data incrementally, avoiding memory overload—ideal for large files, network tasks, and real-time applications. Combining streams with TypeScript's type safety creates a powe

Python vs. JavaScript: Performance and Efficiency ConsiderationsPython vs. JavaScript: Performance and Efficiency ConsiderationsApr 30, 2025 am 12:08 AM

The differences in performance and efficiency between Python and JavaScript are mainly reflected in: 1) As an interpreted language, Python runs slowly but has high development efficiency and is suitable for rapid prototype development; 2) JavaScript is limited to single thread in the browser, but multi-threading and asynchronous I/O can be used to improve performance in Node.js, and both have advantages in actual projects.

The Origins of JavaScript: Exploring Its Implementation LanguageThe Origins of JavaScript: Exploring Its Implementation LanguageApr 29, 2025 am 12:51 AM

JavaScript originated in 1995 and was created by Brandon Ike, and realized the language into C. 1.C language provides high performance and system-level programming capabilities for JavaScript. 2. JavaScript's memory management and performance optimization rely on C language. 3. The cross-platform feature of C language helps JavaScript run efficiently on different operating systems.

Behind the Scenes: What Language Powers JavaScript?Behind the Scenes: What Language Powers JavaScript?Apr 28, 2025 am 12:01 AM

JavaScript runs in browsers and Node.js environments and relies on the JavaScript engine to parse and execute code. 1) Generate abstract syntax tree (AST) in the parsing stage; 2) convert AST into bytecode or machine code in the compilation stage; 3) execute the compiled code in the execution stage.

The Future of Python and JavaScript: Trends and PredictionsThe Future of Python and JavaScript: Trends and PredictionsApr 27, 2025 am 12:21 AM

The future trends of Python and JavaScript include: 1. Python will consolidate its position in the fields of scientific computing and AI, 2. JavaScript will promote the development of web technology, 3. Cross-platform development will become a hot topic, and 4. Performance optimization will be the focus. Both will continue to expand application scenarios in their respective fields and make more breakthroughs in performance.

Python vs. JavaScript: Development Environments and ToolsPython vs. JavaScript: Development Environments and ToolsApr 26, 2025 am 12:09 AM

Both Python and JavaScript's choices in development environments are important. 1) Python's development environment includes PyCharm, JupyterNotebook and Anaconda, which are suitable for data science and rapid prototyping. 2) The development environment of JavaScript includes Node.js, VSCode and Webpack, which are suitable for front-end and back-end development. Choosing the right tools according to project needs can improve development efficiency and project success rate.

Is JavaScript Written in C? Examining the EvidenceIs JavaScript Written in C? Examining the EvidenceApr 25, 2025 am 12:15 AM

Yes, the engine core of JavaScript is written in C. 1) The C language provides efficient performance and underlying control, which is suitable for the development of JavaScript engine. 2) Taking the V8 engine as an example, its core is written in C, combining the efficiency and object-oriented characteristics of C. 3) The working principle of the JavaScript engine includes parsing, compiling and execution, and the C language plays a key role in these processes.

JavaScript's Role: Making the Web Interactive and DynamicJavaScript's Role: Making the Web Interactive and DynamicApr 24, 2025 am 12:12 AM

JavaScript is at the heart of modern websites because it enhances the interactivity and dynamicity of web pages. 1) It allows to change content without refreshing the page, 2) manipulate web pages through DOMAPI, 3) support complex interactive effects such as animation and drag-and-drop, 4) optimize performance and best practices to improve user experience.

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

Video Face Swap

Video Face Swap

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

Hot Tools

SublimeText3 Linux new version

SublimeText3 Linux new version

SublimeText3 Linux latest version

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment