search
HomeWeb Front-endJS TutorialLearn how to use bubbling events to achieve interactive effects: Example analysis of JS bubbling events

Learn how to use bubbling events to achieve interactive effects: Example analysis of JS bubbling events

JS bubbling event example analysis: To master how to use bubbling events to achieve interactive effects, specific code examples are needed

With the development of the Internet, JavaScript (JS) has become An important technology in front-end development. In front-end development, JS bubbling events are often used to achieve interactive effects. This article will introduce the basic concepts and usage of JS bubbling events through specific code examples, and analyze how to use bubbling events to achieve some common interactive effects.

1. Basic concepts of JS bubbling events
In HTML documents, the element structure is often a nested relationship. When an element triggers an event, the event is propagated (bubbled) up to the parent element until it reaches the document root element. This is the basic concept of JS bubbling events. Bubbling events include common click events, mouse move-in and move-out events, keyboard events, etc.

2. Specific usage of bubbling events

  1. Create HTML structure
    First, we need to create some HTML elements with nested relationships to demonstrate the bubbling events transfer process. For example, create a div container and add several div elements inside the container. The code is as follows:
<div id="container">
  <div>元素1</div>
  <div>元素2</div>
  <div>元素3</div>
</div>
  1. Add JS code
    Next, we need to add some JS code for These elements are bound to event listeners so that you can observe the event bubbling up. The code is as follows:
var container = document.getElementById('container');
var elements = container.getElementsByTagName('div');

// 为每个元素绑定事件监听器
for (var i = 0; i < elements.length; i++) {
  elements[i].addEventListener('click', function(event){
    console.log('当前元素:', event.target.innerHTML);
    console.log('冒泡元素:', getBubblingElements(event));
  });
}

// 递归获取所有冒泡元素
function getBubblingElements(event) {
  var bubblingElements = [];
  var currentElement = event.target;
  
  while (currentElement !== document) {
    bubblingElements.push(currentElement.innerHTML);
    currentElement = currentElement.parentNode;
  }
  
  return bubblingElements;
}

In the code, we first obtain the container element and its sub-elements, and then bind a click event listener to each sub-element. When a child element is clicked, the listener prints out the contents of the current element and all bubbled elements.

  1. Testing bubbling events
    Finally, we can test the delivery process of bubbling events by clicking on the div element. When we click on a div element, the console will output the contents of the currently clicked element and all bubbling elements. For example, if element 3 is clicked, the output result is as follows:
当前元素: 元素3
冒泡元素: [元素3, 元素2, 元素1, #container]

The above results indicate that the actual element clicked is element 3, and the bubbling process passes through element 2, element 1 and the container element in sequence. (#container).

3. Use bubbling events to achieve interactive effects
After mastering the basic concepts and specific usage of bubbling events, we can use bubbling events to achieve some common interactive effects. The following takes the cancellation of bubbling, event proxy and event delegation as an example for analysis.

  1. Cancel bubbling
    Sometimes, we want an event to be executed only on the current element without being passed to the parent element. At this time, you can use the stopPropagation method of the event object to cancel the bubbling of the event. For example, we modify the above code so that only the content of the currently clicked element will be output to the console:
// 为每个元素绑定事件监听器
for (var i = 0; i < elements.length; i++) {
  elements[i].addEventListener('click', function(event){
    console.log('当前元素:', event.target.innerHTML);
    console.log('冒泡元素:', getBubblingElements(event));
    event.stopPropagation(); // 取消事件冒泡
  });
}

In the modified code, the stopPropagation method of the event object is added and called in the listener This method can cancel the bubbling delivery of events. In this way, when a div element is clicked, only the current element and its content will be output to the console.

  1. Event proxy
    When there are many DOM elements that need to be bound to the same event listener, you can use event proxy to simplify the code. By binding the event listener to the parent element and using the bubbling event delivery process, the event of the child element is captured on the parent element. For example, we modify the above code to bind the event listener to the container element:
container.addEventListener('click', function(event){
  if (event.target.tagName === 'DIV') { // 只处理div元素的点击事件
    console.log('当前元素:', event.target.innerHTML);
    console.log('冒泡元素:', getBubblingElements(event));
  }
});

In the modified code, bind the event listener to the container element and add the In the code, it is determined that the div element is clicked by judging the tagName of event.target. This way, no matter how many div elements we add to the container, we only need one event listener.

  1. Event delegation
    Event delegation is a way to efficiently utilize bubbling events. You can place a certain type of event listener on the parent element and proxy all child elements of that type. event. For example, we modify the above code and only add a click event listener for the container element to proxy the click events of all div elements:
container.addEventListener('click', function(event){
  if (event.target.tagName === 'DIV') { // 只处理div元素的点击事件
    console.log('当前元素:', event.target.innerHTML);
    console.log('冒泡元素:', getBubblingElements(event));
  }
});

In the modified code, only a click is added for the container element Event listener, and determine whether the tagName of event.target is a div element in the listener code. In this way, no matter how many div elements we add to the container, they will be processed by the event listener proxy.

Summary:
This article introduces the basic concepts and usage of JS bubbling events through specific code examples, and analyzes in detail how to use bubbling events to achieve some common interactive effects, including canceling bubbling. , event proxy and event delegation. Mastering the use of bubbling events can improve the efficiency of interactive effects in front-end development and provide web users with a better user experience. I hope this article will help readers understand and apply JS bubbling events.

The above is the detailed content of Learn how to use bubbling events to achieve interactive effects: Example analysis of JS bubbling events. 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
JavaScript in Action: Real-World Examples and ProjectsJavaScript in Action: Real-World Examples and ProjectsApr 19, 2025 am 12:13 AM

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

JavaScript and the Web: Core Functionality and Use CasesJavaScript and the Web: Core Functionality and Use CasesApr 18, 2025 am 12:19 AM

The main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.

Understanding the JavaScript Engine: Implementation DetailsUnderstanding the JavaScript Engine: Implementation DetailsApr 17, 2025 am 12:05 AM

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python vs. JavaScript: The Learning Curve and Ease of UsePython 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 ResourcesPython 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 WorksFrom 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 ImplementationsJavaScript 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 WorldBeyond 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.

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

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

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.

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)