


Detailed explanation of javascript bubbling events, mouse events and dom instances
About target and currentTarget in bubbling
Target is in the target stage of the event flow; currentTarget is in the capture, target and bubbling stages of the event flow. Only when the event flow is in the target stage, the two directions are the same. When it is in the capturing and bubbling stages, target points to the clicked object and currentTarget points to the parent of the current event.
<p id="outer" style="background:#099"> <p>我是目标p</p> ----点击这部分,输出:e.target.tagName : P || e.currentTarget.tagName : p <p id="inner" style="background:#9C0">我是目标p</p> ----点击这部分,输出:e.target.tagName : P || e.currentTarget.tagName : p <br> ----点击这部分,输出:e.target.tagName : p || e.currentTarget.tagName : p </p> //看下第二个变列: <p id="outer" style="background:#099"> <p>我是目标p</p> ----点击这部分,输出:e.target.tagName : p || e.currentTarget.tagName : p <p id="inner" style="background:#9C0">我是目标p</p> ----点击这部分,输出:e.target.tagName : P || e.currentTarget.tagName : p <br> ----点击这部分,输出:e.target.tagName : p || e.currentTarget.tagName : p </p>
function getObj(id) { return document.getElementById(id); } function addEvent(obj, event, fn) { if(window.attachEvent) { obj.attachEvent("on" + event, fn); } else if(window.addEventListener) { obj.addEventListener(event, fn, false); } } function test(e) { alert("e.target.tagName : " + e.target.tagName + "\n e.currentTarget.tagName : " + e.currentTarget.tagName); } var outer = getObj("outer"); var inner = getObj("inner"); //addEvent(inner, "click", test); addEvent(outer, "click", test);
The difference between IE and DOM
DOM Get the target event.target event.srcElementGet the character code event.charCode event.keyCode
Prevent the default behavior event.prevetDefault() event.returnvalue=falseBubbling event.stopPropagation() event.cancelBubble= true
About blocking the default behavior, for example, if you don’t want the menu to pop up when the user right-clicks the mouse, you can use the blocking default behavior:
document.body.oncontextmenu=function(event) { if(isIE) { var oEvent=window.event; oEvent.returnValue=false; //也可以直接是return false;阻止默认行为 } else { oEvent.preventDefault(); } }
Mouse event
<p>use your mouse to click and double click the red square</p> <p style="width:100px;height:100px;background:red" onmouseover="handleEvent(event)" onmouseout="handleEvent(event)" onmousedown="handleEvent(event)" onmouseup="handleEvent(event)" onclick="handleEvent(event)" ondblclick="handleEvent(event)" id="p1" > </p> <p><textarea id="txt1" rows="5" cols="45"></textarea></p> <!--检测键盘事件--> <p><input type="text" id="textbox" onkeydown="handle(event)" onkeypress="handle(event)" onkeyup="handle(event)" ></p> <p><textarea id="txt2" rows="10" cols="45"></textarea></p>
js file is as follows:
function handleEvent(event) { var oText=document.getElementById('txt1'); oText.value+= "\n"+event.type; oText.value+= "\n target is "+(event.srcElement||event.target).id; oText.value+="\n at ("+event.clientX+","+event.clientY+")in the client"; oText.value+="\n at ("+event.screenX+","+event.screenY+")in the client"; oText.value+="\n button down is"+event.button; var arrKeys=[]; oText.value+="\n relatedTarget is"+event.relatedTarget.tagName; //event.relatedTarget.tagName可以判断鼠标的来源和出处 } function handle(event) { var oText2=document.getElementById('txt2'); oText2.value+="\n"+event.type; var arrKeys=[]; if(event.shiftKey){arrKeys.push("Shift");} if(event.ctrlKey){arrKeys.push("Ctrl");} if(event.altKey){arrKeys.push("Alt");} oText2.value+="\n keydown is "+arrKeys; }
The above is the detailed content of Detailed explanation of javascript bubbling events, mouse events and dom instances. For more information, please follow other related articles on the PHP Chinese website!

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.

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 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.

C and JavaScript achieve interoperability through WebAssembly. 1) C code is compiled into WebAssembly module and introduced into JavaScript environment to enhance computing power. 2) In game development, C handles physics engines and graphics rendering, and JavaScript is responsible for game logic and user interface.

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.

Python is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.

C and C play a vital role in the JavaScript engine, mainly used to implement interpreters and JIT compilers. 1) C is used to parse JavaScript source code and generate an abstract syntax tree. 2) C is responsible for generating and executing bytecode. 3) C implements the JIT compiler, optimizes and compiles hot-spot code at runtime, and significantly improves the execution efficiency of JavaScript.

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.


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

SublimeText3 Linux new version
SublimeText3 Linux latest version

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.

Atom editor mac version download
The most popular open source editor

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SublimeText3 Mac version
God-level code editing software (SublimeText3)
