< ;STYLE type='text/css'>
.css1{
display:block;
width:100px;
height:100px;
background-color:blue;
}
.css2{
display:block;
width:100px;
height:100px;
background-color:red;
}
tt
<script> <BR>$(document).ready(function(){ <BR>$("#freee").hover( function(){ <BR>$(this).addClass("css2"); <BR>}, function(){ <BR>$(this).removeClass("css2"); <BR>}); <BR>}); <BR></script>
Find me: using selectors and events
jQuery provides two ways to select elements of html. The first is to use CSS and Xpath selectors to combine to form a string and send it to jQuery's constructor (such as: $("div > ul a")) ;The second method is to use several methods of the jQuery object. These two methods can also be used in combination.
To test these selectors, let’s try to select and modify the first ordered list in our starterkit.html.
Initially, we need to select the list itself, this list There is an ID called "orderedlist", and the usual javascript writing method is document.getElementById("orderedlist"). In jQuery, we do this:
$(document).ready(function() {
$("#orderedlist").addClass("red");
}); Here a CSS style red in the starterkit is attached to the orderedlist (Translator Keel's Note: Refer to the core in the css directory in the test package .css, in which the red style is defined). Therefore, after you refresh the starterkit.html, you will see that the background color of the first ordered list changes to red, while the second ordered list does not change.
Now , let's add some new styles to the child nodes of the list.
$(document).ready(function() {
$("#orderedlist > li").addClass("blue" );
}); In this way, all li in the orderedlist are appended with the style "blue".
Now let’s do something a little more complicated. When the mouse is placed on the li object and moved away, the style will be switched, but it will only take effect on the last element of the list.
$(document).ready(function() {
$("#orderedlist li:last").hover(function() {
$(this).addClass("green" );
}, function() {
$(this).removeClass("green");
});
}); There are also a large number of similar CSS and XPath examples, more Many examples and lists can be found here. (Translator Keel’s note: Read this article to get started. Cultivation depends on the individual. If you want to know more after getting started, you must read the links of this paragraph sooner or later! You won’t have to translate it again...^_ ^!)
Every onXXX event is valid, such as onclick, onchange, onsubmit, etc., all have jQuery equivalent representation methods (Translator Keel's note: jQuery doesn't like onXXX, so they are changed to XXX and removed on).

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

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.

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.

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 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.

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.


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

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.

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.

SublimeText3 English version
Recommended: Win version, supports code prompts!

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
