Web Front-endJS TutorialA clever talk about the two public members of event in JavaScript events: properties and methodsA clever talk about the two public members of event in JavaScript events: properties and methods
The public members of events in DOM include properties and methods. The types of events triggered are different, and the available properties and methods are different. However, all events in the DOM have public members. This article mainly introduces the public members (properties and methods) of events in javaScript events. It is very good and has reference value. Friends in need can refer to it
1. Public members of the event object
1. Public members of the event in the DOM
The event object contains and creates it Properties and methods related to specific events. The types of events triggered are different, and the available properties and methods are different. However, all events in the DOM have the following public members.
a. Compare currentTarget and target
Inside the event handler, the object this is always equal to the value of currentTarget, while target only contains the actual target of the event .
For example: There is a button on the page, and a click event is registered in the body (the parent node of the button). When the button is clicked, the click event will bubble up to the body for processing.
<body>
<input id="btn" type="button" value="click"/>
<script>
document.body.onclick=function(event){
console.log("body中注册的click事件");
console.log("this===event.currentTarget? "+(this===event.currentTarget)); //true
console.log("currentTarget===document.body?"+(event.currentTarget===document.body)); //true
console.log('event.target===document.getElementById("btn")? '+(event.target===document.getElementById("btn"))); //true
}
</script>
</body>
The running result is:
b. Through the type attribute, it can be processed in a function Multiple events.
Principle: By detecting the event.type attribute, different events are processed differently.
Example: Define a handler function to handle three types of events: click, mouseover, mouseout.
<body>
<input id="btn" type="button" value="click"/>
<script>
var handler=function(event){
switch (event.type){
case "click":
alert("clicked");
break;
case "mouseover":
event.target.style.backgroundColor="pink";
break;
case "mouseout":
event.target.style.backgroundColor="";
}
};
var btn=document.getElementById("btn");
btn.onclick=handler;
btn.onmouseover=handler;
btn.onmouseout=handler;
</script>
</body>
Running effect: Click the button and a pop-up box will pop up. When the mouse passes over the button, the button background color changes to pink; when the mouse leaves the button, the background color returns to the default.
c, stopPropagation() and stopImmediatePropagation() comparison
Same: stopPropagation() and stopImmediatePropagation() can both be used to cancel further capturing or bubbling of events.
Difference: The difference between the two is that when an event has multiple event handlers, stopImmediatePropagation() can prevent subsequent event handlers from being called.
Example:
<body>
<input id="btn" type="button" value="click"/>
<script>
var btn=document.getElementById("btn");
btn.addEventListener("click",function(event){
console.log("buttn click listened once");
// event.stopPropagation();//取消注释查看效果
// event.stopImmediatePropagation();//取消注释查看效果
},false);
btn.addEventListener("click",function(){
console.log("button click listened twice");
},false);
document.body.onclick= function (event) {
console.log("body clicked");
}
</script>
</body>
Operation effect:
d、eventPhase
The eventPhase value is 1 in the capture phase, 2 in the target phase, and 3 in the bubbling phase.
Example:
<body>
<input id="btn" type="button" value="click"/>
<script>
var btn=document.getElementById("btn");
btn.onclick= function (event) {
console.log("按钮DOM0级方法添加事件处理程序eventPhase值为？"+event.eventPhase);
}
btn.addEventListener("click",function(event){
console.log("按钮DOM2级方法添加事件处理程序，且addEventListener第三个参数为true时eventPhase值为？"+event.eventPhase);
},true);
btn.addEventListener("click",function(event){
console.log("按钮DOM2级方法添加事件处理程序，且addEventListener第三个参数为false时eventPhase值为？"+event.eventPhase);
},false);
document.body.addEventListener("click", function (event) {
console.log("body上添加事件处理程序，且在捕获阶段eventPhase值为？"+event.eventPhase);
},true);
document.body.addEventListener("click", function (event) {
console.log("body上添加事件处理程序，且在冒泡阶段eventPhase值为？"+event.eventPhase);
},false);
</script>
Operation effect:
2, Public members of events in IE
The properties and methods of events in IE, like DOM, vary with event types, but there are also some public members that all objects have, and these Most members have corresponding DOM attributes or methods.
The above is the javaScript event learning summary introduced by the editor (4) related knowledge of the public members (properties and methods) of event. I hope it will be useful to everyone. Help, if you have any questions please leave me a message!
Related recommendations:
The above is the detailed content of A clever talk about the two public members of event in JavaScript events: properties and methods. For more information, please follow other related articles on the PHP Chinese website!
Node.js Streams with TypeScriptApr 30, 2025 am 08:22 AMNode.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 ConsiderationsApr 30, 2025 am 12:08 AMThe 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 LanguageApr 29, 2025 am 12:51 AMJavaScript 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?Apr 28, 2025 am 12:01 AMJavaScript 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 PredictionsApr 27, 2025 am 12:21 AMThe 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 ToolsApr 26, 2025 am 12:09 AMBoth 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 EvidenceApr 25, 2025 am 12:15 AMYes, 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 DynamicApr 24, 2025 am 12:12 AMJavaScript 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.
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
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.
MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft
Zend Studio 13.0.1
Powerful PHP integrated development environment
SublimeText3 English version
Recommended: Win version, supports code prompts!
