JQuery Methods & Return Values: A Comprehensive Guide

Aug 14, 2025 by Henrik Larsen 54 views

Trực tuyến 🐓杉惺厥涤燃变量2-2Discussion category: thamduongcanh-lang, stoye

Hey guys! Let's dive into the awesome world of jQuery, a powerful and lightweight JavaScript library designed to make web development a breeze. We'll be breaking down some of the most commonly used jQuery methods and their return values, helping you become a jQuery master in no time!

1. jQuery选择器方法 (Selector Methods)

jQuery selectors are your best friends when it comes to grabbing those HTML elements on your page. The most fundamental selector is the $ function. Think of it as your magic wand for selecting elements based on their class, ID, tag name, or even more complex CSS selectors. For example, if you want to snag all elements with the class "className," you'd use:

var elements = $('.className');

Now, what do you get back from this magical incantation? Well, the return value here is a jQuery object. But not just any object – it's a collection of all the elements that matched your selector. This jQuery object is super versatile. It allows you to perform actions on all the selected elements at once, like changing their styles, adding event listeners, or even animating them. This is what makes jQuery so efficient and fun to use. It’s like herding cats, but in a good way – you can control them all with a single command!

This collection behaves a bit like an array, meaning you can access specific elements using their index (though you usually won't need to). The key takeaway here is that you're working with a jQuery object, not just a raw DOM element, which unlocks a whole bunch of jQuery-specific methods.

Understanding the return value as a jQuery object is crucial because it’s the foundation for chaining methods – a core concept in jQuery that lets you write incredibly concise and readable code. Imagine selecting elements, changing their color, and then fading them out all in a single line! That's the power of jQuery's method chaining, and it all starts with those selector methods and their jQuery object return values.

So, next time you use a jQuery selector, remember you're not just picking elements; you're creating a jQuery object that gives you superpowers over those elements. Use it wisely!

2. 事件处理 (Event Handling)

Event handling in jQuery is a total game-changer! Say goodbye to messy, verbose JavaScript event listeners, and hello to jQuery's sleek and intuitive syntax. The .on() and .off() methods are your go-to tools for attaching and detaching event listeners, respectively. Let’s say you want to trigger an alert when a button is clicked. Here’s how you’d do it:

$('#button').on('click', function() {
 alert('Button clicked!');
});

Simple, right? Now, what’s the return value of the .on() method? This is where it gets cool: it returns the current jQuery object! "Wait, what?" you might be thinking. "Why is that important?" Well, this is the key to jQuery’s famous method chaining. Because .on() returns the jQuery object, you can immediately chain other jQuery methods onto it. It’s like building a Lego structure – each method seamlessly connects to the previous one.

For example, you could add a click handler and then immediately change the button’s text, all in one line! This makes your code super readable and efficient. Without the jQuery object return value, you’d have to break this into multiple lines, which is less elegant and harder to maintain.

The .off() method, used to detach event listeners, also returns the jQuery object. This consistency in return values is a hallmark of jQuery's design, making it a joy to work with. Think of it like this: each jQuery method does its job and then politely hands the control back to you (in the form of the jQuery object) so you can keep the party going.

So, the next time you're setting up event listeners with jQuery, remember that .on() and .off() aren't just attaching and detaching functionality; they're also passing the torch (the jQuery object) so you can chain methods and create beautiful, concise code. Keep those chains flowing!

3. CSS 操作 (CSS Manipulation)

CSS manipulation is a core part of web development, and jQuery makes it incredibly straightforward. The .css() method is your Swiss Army knife for getting and setting CSS properties. You can use it to read the current value of a property or set a new value, or even set multiple properties at once. Let’s say you want to change the text color of an element with the ID "element" to red. You'd use this code:

$('#element').css('color', 'red');

Super simple, right? But here’s the kicker: the return value of .css() depends on how you use it. If you pass in only a property name (like 'color'), jQuery will return the current value of that property for the first element in the matched set. So, $('#element').css('color') would return something like 'rgb(255, 0, 0)' (or the hexadecimal equivalent). This is incredibly useful for dynamically checking styles.

However, if you pass in a property name and a value (like 'color', 'red'), or if you pass in an object containing multiple properties and values, then .css() does something different. It sets the specified CSS properties for all elements in the jQuery collection and then returns the current jQuery object! Yes, you guessed it – this enables method chaining. It’s the gift that keeps on giving!

This clever design allows you to chain CSS manipulations with other jQuery methods. For instance, you could set the color to red, the font size to 20 pixels, and then fade the element out, all in a single, elegant line of code. This makes your code not only shorter but also more readable. It’s like writing poetry with CSS!

The consistent return value of the jQuery object when setting styles is a key part of what makes jQuery so expressive and efficient. It allows you to build complex interactions with ease, keeping your code clean and maintainable. So, next time you’re styling elements with jQuery, remember that .css() is not just changing appearances; it’s also giving you the power to chain operations and create dynamic visual effects with minimal code.

4. DOM 操作 (DOM Manipulation)

DOM manipulation is where jQuery really shines, guys! Forget the verbose and often clunky native JavaScript DOM methods. jQuery provides a rich set of functions to add, remove, and modify elements in your HTML structure with ease. Methods like .append(), .prepend(), .remove(), .addClass(), .removeClass(), and .attr() are just the tip of the iceberg. Let's say you want to add a new <div> element as a child to an element with the ID "parent". You'd use:

$('#parent').append('<div>New child</div>');

Boom! New element added. Now, what’s the return value of .append()? You guessed it – it’s the current jQuery object! This might seem repetitive at this point, but it’s the cornerstone of jQuery’s method chaining. The fact that almost all DOM manipulation methods return the jQuery object means you can string together a series of operations seamlessly.

Imagine you need to create a new list item, add some text to it, append it to a list, and then add a class to the list. With jQuery, you can do all of that in a single, fluid chain. This makes your code incredibly concise and easy to read. It's like a domino effect – one method triggers the next, resulting in a beautifully constructed DOM.

This consistent return value also simplifies complex operations. For example, you can move an element from one part of the DOM to another and then immediately apply some styling or event listeners. The possibilities are endless! The key takeaway is that jQuery’s DOM manipulation methods are not just about changing the structure of your page; they’re about providing a powerful, chainable interface for doing so.

So, the next time you’re wrestling with the DOM, remember that jQuery is your ally. And remember that the jQuery object return value is your secret weapon, allowing you to chain methods and perform complex manipulations with minimal code and maximum elegance. Keep manipulating those elements like a pro!

5. AJAX 请求 (AJAX Requests)

AJAX requests are essential for modern web applications, allowing you to fetch data from the server without reloading the entire page. jQuery simplifies this process with its .ajax() method, a powerful and versatile tool for making asynchronous HTTP requests. You can customize every aspect of the request, from the URL and HTTP method to the data you send and the callbacks you want to execute when the request completes.

Let’s say you want to fetch some data from an API endpoint. Here’s how you’d do it using jQuery:

$.ajax({
 url: 'https://api.example.com/data',
 method: 'GET',
 success: function(data) {
 console.log(data);
 }
});

Pretty clean, huh? But what about the return value? This is where it gets a bit different from the previous methods. $.ajax() returns a jqXHR object. Now, what’s a jqXHR object? Think of it as a supercharged promise object that jQuery provides specifically for AJAX requests. It gives you fine-grained control over the request and its status.

The jqXHR object has several useful methods, like .done(), .fail(), and .always(), which allow you to attach callbacks to be executed when the request succeeds, fails, or completes, respectively. This is a more modern and flexible way to handle AJAX callbacks compared to the traditional success, error, and complete options in the $.ajax() settings object.

For example, you could rewrite the previous example using the jqXHR object’s .done() method:

$.ajax({
 url: 'https://api.example.com/data',
 method: 'GET'
}).done(function(data) {
 console.log(data);
});

This is often considered cleaner and more readable, especially when dealing with complex AJAX interactions. The jqXHR object also has methods like .abort() to cancel the request and .state() to get the current state of the request.

So, while $.ajax() doesn’t return the jQuery object for chaining, it gives you something even more valuable: the jqXHR object, which provides a robust interface for managing asynchronous requests. This makes jQuery’s AJAX functionality not only easy to use but also incredibly powerful and flexible. Next time you're fetching data from the server, remember the jqXHR object – it’s your key to mastering asynchronous communication in jQuery.

6. 动画效果 (Animation Effects)

Animation effects can bring your website to life, and jQuery makes it incredibly easy to create smooth and engaging animations with just a few lines of code. Methods like .fadeIn(), .fadeOut(), .slideUp(), .slideDown(), and .animate() provide a wide range of pre-built animation effects, as well as the ability to create custom animations. Let’s say you want to fade out an element with the ID "element". You'd simply use:

$('#element').fadeOut();

Bam! Instant fade-out. Now, what's the return value here? You guessed it (again!) – it's the current jQuery object! This consistent return value allows you to chain animation methods with other jQuery operations, creating complex and visually appealing effects with minimal code.

For example, you could fade out an element, and then remove it from the DOM, all in a single chain. This makes your code not only concise but also expressive and easy to understand. It’s like choreography for your web page, with each method seamlessly transitioning into the next.

The .animate() method is particularly powerful because it allows you to create custom animations by specifying the CSS properties you want to animate and their target values. This gives you complete control over the animation, allowing you to create unique and engaging visual effects.

Because all these animation methods return the jQuery object, you can easily combine them with other jQuery functions. For instance, you could fade in an element, animate its position, and then fade it out, all in a single, fluid chain. This is where jQuery truly shines, making complex animations accessible to everyone.

So, the next time you're looking to add some flair to your website, remember jQuery’s animation methods. And remember that the jQuery object return value is your secret weapon, allowing you to create stunning visual effects with elegance and efficiency. Get those animations flowing!

7. 获取和设置值 (Getting and Setting Values)

Getting and setting values of form elements is a common task in web development, and jQuery’s .val() method makes it a breeze. This method is your go-to tool for working with form inputs, textareas, select boxes, and more. Whether you need to read the current value of an input field or set a new value, .val() has you covered. Let’s say you want to get the current value of an input element with the ID "input". You’d use:

var inputValue = $('#input').val();

Simple enough. But what if you want to set the value of the input? No problem! Just pass a value as an argument:

$('#input').val('New Value');

Easy peasy. Now, let's talk about the return value, because, as you might expect, it depends on how you use .val(). If you call .val() without any arguments, it returns the current value of the first element in the matched set. This is incredibly useful for reading user input or dynamically checking the state of a form.

However, if you call .val() with a value argument, it sets the value of all elements in the jQuery collection and then returns the current jQuery object! Ding ding ding! You know what that means – method chaining is back in action! This allows you to chain .val() with other jQuery methods, making your code even more concise and readable.

For example, you could set the value of an input, and then immediately trigger a change event, all in one line. This is incredibly useful for creating dynamic forms and interactions. The consistent behavior of .val(), returning either the value or the jQuery object, is a testament to jQuery’s thoughtful design.

So, the next time you’re working with form elements, remember jQuery’s .val() method. And remember that the return value is your friend, allowing you to either read the current value or chain operations and create dynamic forms with ease. Keep those forms flowing smoothly!

总结 (Conclusion)

jQuery is a powerhouse for front-end development, providing a plethora of powerful and convenient features. By understanding the return values of different methods, developers can perform DOM operations, event handling, and data interactions more efficiently. In practice, using these methods reasonably will greatly improve work efficiency while maintaining the readability and maintainability of the code. Hope this article can help you better master jQuery and maximize its advantages!

So there you have it, guys! jQuery is an amazing library, and knowing these method return values will seriously level up your web development game. Keep practicing, keep chaining, and keep building awesome things! Happy coding!

I've also included a list of Spring Boot projects. However, please note that these projects are not directly related to the main topic of jQuery methods and return values. If you'd like, I can create a separate article focusing on Spring Boot projects or integrate a brief overview into this article while maintaining its primary focus on jQuery.

SpringBoot 项目 spring-boot-quick - 基于 SpringBoot 的快速学习示例，整合开源框架，如：RabbitMQ、Kafka、Jpa、Redis、Oauth2、Swagger、Jsp、Docker、k3s、k3d、k8s、Mybatis 加解密插件、异常处理、日志输出、多模块开发、多环境打包、缓存 Cache、爬虫、JWT、GraphQL、Dubbo、 Zookeeper 和 Async 等等. SpringBootCodeGenerator - 基于 SpringBoot + Freemarker 的 JAVA 代码生成器，以释放双手为目的，支持 MySQL/Oracle/PgSQL 三大数据库， 用DDL-SQL 语句生成 JPA、JdbcTemplate、Mybatis、MybatisPlus、BeetlSQL 等相关代码.
jetlinks-community - 基于 Java8、Spring Boot 2.x、WebFlux、Netty、Vert.x、Reactor 等开发，是一个全响应式的企业级物联网平台。支持统一物模型管理，多种设备，多种厂家，统一管理。统一设备连接管理，多协议适配(TCP、MQTT、UDP、CoAP、HTTP等)。屏蔽网络编程复杂性，灵活接入不同厂家不同协议等设备；实时数据处理，设备告警，消息通知,数据转发，地理位置,数据可视化等.
spring-boot-projects - Spring Boot 的入门学习教程、实战项目教程.
SpringBoot-Learning - Spring Boot 教程.
spring-boot-demo - 深入学习并实战 Spring Boot 的项目.
SpringAll - Spring 全家桶学习项目.
jeecg-boot - 一款基于代码生成器的低代码开发平台.
PlayEdu - 一款适用于搭建内部培训平台的开源系统.
vlife - 企业级低代码快速开发平台.
mybatis-plus-generator-ui - 对 Mybatis-Plus-Generator 进行封装，通过 Web UI 快速生成兼容 Spring Boot，Mybatis-Plus 框架的各类业务代码.
mybatis-plus-code-generator - MyBatis-Plus 代码生成器.
hsweb-framework - 一个基于 Spring-Boot 2.x 开发，首个使用全响应式编程的企业级后台管理系统基础项目.
open-sign-old - 开放签电子签章系统.
admin3 - 一个轻巧的后台管理框架，项目后端基于 Java17、SpringBoot 3.0，前端基于 TypeScript、Vite3、Vue3、Element Plus.
nginx-gui - 一个基于 SpringBoot 实现的 Nginx 可视化管理项目.
JApiDocs - 无需额外注解的 SpringBoot API 文档生成工具.
jianmu - 一个面向 DevOps 领域的极易扩展的开源无代码(图形化)/低代码( GitOps )工具.
smart-admin - 基于 SpringBoot + Sa-Token + Mybatis-Plus 和 Vue3 + Vite5 + Ant Design Vue 4.x 中后台解决方案.
maku-generator - 一款低代码生成器.
reader - 一款图书阅读工具.
magic-api - 一个基于 Java 的接口快速开发框架.
opsli-boot - 一个基于 SpringBoot、Vue 的低代码快速开发平台.
eladmin - 一个基于 SpringBoot、SpringBoot Jpa、JWT、Spring Security、Redis、Vue 的前后端分离的后台管理系统.
erupt - 一个低代码全栈类框架，它使用Java 注解动态生成页面以及增、删、改、查、权限控制等后台功能.
sz-boot-parent - 一个开源 RBAC 中后台框架，专为现代应用设计.
book_novels - 基于 SpringBoot + MybatisPlus + Jsoup + MySQL 实现的小说阅读网站.
xingyun - 基于 SpringBoot 框架的中小企业完全开源的 ERP.
工作流 OA 项目
RuoYi-activiti - 基于 Activiti 6.0，集流程设计、流程部署、流程执行、任务办理、流程监控于一体的开源工作流开发平台.
agile-bpm-basic - 基于 JDK17、Activiti7、Vue3、TS、Vite、ElementPlus 实现的工作流、低代码、快速开发平台。 在线文档
JFlow - 适合中国国情的工作流引擎.
jw-workflow-engine - 工作流设计器，自研表单及流程设计，UI 简洁美观.
ferry - 集工单统计、任务钩子、权限管理、灵活配置流程与模版等等于一身的开源工单系统.
RuoYi-Flowable-Plus - 基于 RuoYi-Vue-Plus 进行二次开发扩展 Flowable 工作流功能，支持在线表单设计和丰富的工作流程设计能力.
cxygzl - 基于 Flowable 的开箱即用的低代码开源专业工作流引擎。在线文档
flowlong - 工作流引擎、Json 格式实例模型、仿飞书钉钉审批流程设计器.
oa_system - 一个 OA 办公自动化系统.
JFinalOA - 基于 JFinal 框架开发的企业办公系统.
mldong - 基于 SpringBoot + Vue3 实现的快速开发平台、工作流引擎.
数据操作项目
DataX - 阿里云 DataWorks 数据集成的开源版本，实现了包括 MySQL、Oracle、OceanBase、SqlServer、Postgre、HDFS、Hive、ADS、HBase、TableStore(OTS)、MaxCompute(ODPS)、Hologres、DRDS 等各种异构数据源之间高效的数据同步功能.
TDengine - TDengine 是一款开源、高性能、云原生的时序数据库（Time Series Database, TSDB）, 它专为物联网、车联网、工业互联网、金融、IT 运维等场景优化设计.
dsq - 一个命令行工具，可对数据文件进行 SQL 查询，支持 JSON、CSV、Excel、Parquet 等数据文件.
dbeaver - 免费的通用数据库工具和 SQL 客户端.
milvus - 一个云原生的矢量数据库，为下一代人工智能应用提供存储空间.
minio - 一个高性能的对象存储，它与 Amazon S3 云存储服务的 API 兼容.
Chat2DB - 智能的通用数据库工具和 SQL 客户端.
otter - 阿里巴巴分布式数据库同步系统(解决中美异地机房).
dynamic-datasource - 一个基于 SpringBoot 的快速集成多数据源的启动器.
强大的 SQL 注入工具.
datagear - 数据可视化分析平台，自由制作任何您想要的数据看板.
sqlmap - 一款强大的 SQL 注入工具.
slashbase - 支持 MySQL、PostgreSQL&MongoDB 的数据库管理 IDE.
SmartSqlT - 一款方便、快捷的数据库文档查询、导出工具.
dbsyncer - 一款开源的数据同步中间件.
drawdb - 免费、简单且直观的在线数据库设计工具和 SQL 生成器.
dbgate - 跨平台数据库管理器.
beekeeper-studio - 适用于 MySQL、Postgres、SQLite、SQL Server 等的现代且易于使用的 SQL 客户端.
chartdb- 一个功能强大的、基于网页的数据库图表编辑器.
anyclient-web - 一款开源、支持 Web 和客户端，能够连接各种类型数据服务的管理软件.
sqlitebrowser - 一款实用的 SQLite 数据库桌面管理工具.
sqlite-web - 基于 Python 实现的在线 SQLite 数据库操作工具.
sqlpage - 一款基于 SQL 的网页应用构建器.
cloudbeaver - 一款 
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