Since then, I've found many ways to let visitors toggle stylesheets by clicking somewhere with their mouse. But recently I want to write a tutorial on how to write simple code using jQuery to implement it.
I will walk you through the entire process step by step, not only because I want to show you an introduction to jQuery code, but also to reveal some of the advanced features in the jQuery library.
First, the code
$(document).ready (function() {
$('.styleswitch').click(function()
{
switchStylestyle(this.getAttribute("rel"));
return false;
} );
var c = readCookie('style');
if (c) switchStylestyle(c);
});
function switchStylestyle(styleName)
{
$( 'link[@rel*=style][title]').each(function(i)
{
this.disabled = true;
if (this.getAttribute('title') == styleName ) this.disabled = false;
});
createCookie('style', styleName, 365);
}
The other part not mentioned here is that you will The functions that create and read cookies are seen later.
Familiar opening
$(document).ready(function(){ $('.styleswitch').click(function()... tells jQuery "Find all containing objects as quickly as possible" element named 'styleswitch' and execute a function when they are clicked by the mouse.
Looks good. When the mouse clicks on the pre-specified element, the switchStylestyle function will be called. From now on that is the focus.
What does this sentence mean?
My mind was a little stuck when I saw this code for the first time:
$('link[@rel*=style]').each(function(i) {
After searching on the Internet, I came up empty-handed. Finally, I had to find John Resig, the author of jQuery, and consult him.
He directly gave me the page address of the jQuery website, which explained several jQuery features. The advanced features (xpath) can be used to find and manipulate several elements in the page.
If you have seen these things, you will understand that the meaning of the mysterious code above is to tell jQuery to "find all elements with rel attributes and A link element whose attribute value string contains 'style'".
Let's see how to write a page that contains one main style sheet and two backup style sheets:
We can Seeing that all style sheets contain a rel attribute containing the 'style' string, the result is clear at a glance.
What is the next step? Iterate through all these stylesheet links and execute the code in the next line:
this.disabled = true;if (this.getAttribute('title') == styleName) this.disabled = false;"Disable all styles first table link, and then open any style sheet whose title attribute value is the same as the string passed by the switchStylestyle function."
It’s a handful, but it’s very effective.
Now all we need to ensure is that those stylesheets exist and are valid.
Full code and demo
Since Kelvin Luck has already written this code, I won’t repeat it here.
DEMO
I believe Kelvin got his inspiration from this website, and we can just see if using other tools to implement this function is more complicated and verbose than jQuery.
Complete styleswitch.js
/**
* Styleswitch stylesheet switcher built on jQuery
* Under an Attribution, Share Alike License
* By Kelvin Luck ( http://www.kelvinluck.com/ )
**/
(function($)
{
$(document).ready(function() {
$('.styleswitch').click(function()
{
switchStylestyle(this.getAttribute("rel"));
return false;
});
var c = readCookie('style');
if (c) switchStylestyle(c);
});
function switchStylestyle(styleName)
{
$('link[@rel*=style][title]').each(function(i)
{
this.disabled = true;
if (this.getAttribute('title') == styleName) this.disabled = false;
});
createCookie('style', styleName, 365);
}
})(jQuery);
// cookie functions http://www.quirksmode.org/js/cookies.html
function createCookie(name,value,days)
{
if (days)
{
var date = new Date();
date.setTime(date.getTime() (days*24*60*60*1000));
var expires = "; expires=" date.toGMTString();
}
else var expires = "";
document.cookie = name "=" value expires "; path=/";
}
function readCookie(name)
{
var nameEQ = name "=";
var ca = document.cookie.split(';');
for(var i=0;i {
var c = ca[i];
while (c.charAt(0)==' ') c = c.substring(1,c.length);
if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
}
return null;
}
function eraseCookie(name)
{
createCookie(name,"",-1);
}
// /cookie functions

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.

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 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 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 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.


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.

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

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.

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),

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment