This time I will show you how jQuery's Read() method replaces JS, and jQuery's Read() method replaces JSWhat are the precautions?The following is a practical case, let's take a look.
As we all know, the ready method in jQuery executes the code in the DOM immediately after it is completely downloaded. Because it waits for all DOM elements to be loaded before executing the given function, you can be sure that methods that attempt to operate and access element nodes will be executed. This article will introduce to you how to use jQuery's Read() method instead of native JS. Let's take a look.
Before jQuery 3.0, the classic usage of ready was to use an anonymous function, like this:
$(document).ready(function() { // Handler for .ready() called. });
jQuery 3.0 ready() changes
Before jQuery 3.0 was released, there were several methods called ready methods:
Operating on the document element: $(document).ready (handler);
Operate on empty elements: $().ready(handler);
Or directly (that is, not on a specific element ) Operation: $(handler);
All named variants above are functionally equivalent. No matter which element it is, its specified handler will be called after the DOM is loaded. In other words, the completion of DOM loading here does not mean that a specific element in the document, such as the img element, has been loaded. On the contrary, what it means here is that the entire DOM tree has been loaded.
In jQuery 3.0, all ready methods except $(handler)
are deprecated.
Official statement:
This is because the selector is not connected to ready(), which is not only inefficient but also causes the browser engine to block the method. Behavior makes incorrect assumptions.
The difference between the ready event and the load event
The ready event is triggered when the DOM is loaded and the element can be safely accessed. On the other hand, the load event is triggered after the DOM and all resources are loaded.
You can use the load event as follows:
$(window).on("load", function(){ // Handler when all assets (including images) are loaded });
In this case, not only do you have to wait until the DOM structure can be fully accessed, but you also need to wait until all image resources are completely loaded (the loading time depends on image file size) to execute the function.
You may not need the load event for normal DOM operations, but if you want to display a rotating loader style before all resources are loaded, for example, or you want to use JS to calculate the image size, this might be a good choice.
You may not need jQuery.ready()
The ready method ensures that code is only executed when all DOM elements can be safely manipulated . But what does this mean? This means that when the js code you want to execute is embedded in a certain fragment in HTML, the browser must also load the following elements before it can be executed.
Like the following example:
nbsp;html> <meta> <title>.ready() tutorial</title> <script></script> <script> $(function(){ // .ready() callback, is only executed when the DOM is fully loaded var length = $("p").length; // The following will log 1 to the console, as the paragraph exists. // This is the evidence that this method is only called when the // DOM is fully loaded console.log(length); }); </script> <p>I'm the content of this website</p>
If the javascript code you want to execute is placed at the end of the body, you may not need to use ready()
Method, because the DOM element you may be trying to manipulate and access when the browser parses the javascript has already been loaded:
nbsp;html> <meta> <title>.ready() tutorial</title> <p>I'm the content of this website</p> <script></script> <script> var length = $("p").length; // The following will log 1 to the console, as the paragraph exists. console.log(length); </script>
Native JavaScript ready() replacement
For modern browsers and IE9, you can achieve the same functionality of ready()
by listening to the DOMContentLoaded event:
document.addEventListener("DOMContentLoaded", function(){ // Handler when the DOM is fully loaded });
However, please note that if the event has already been emitted , the callback will not be executed. To ensure that the callback always runs, jQuery checks the "readyState" attribute of the document reference), and if the attribute value changes to complete, the callback function is executed immediately:
var callback = function(){ // Handler when the DOM is fully loaded }; if ( document.readyState === "complete" || (document.readyState !== "loading" && !document.documentElement.doScroll) ) { callback(); } else { document.addEventListener("DOMContentLoaded", callback); }
Includes the domReady library, which has been implemented Got this solution.
Old versionIE browser
For browsers IE8 and below, you can use the onreadystatechange event to Monitor the readyState attribute of the document:
document.attachEvent("onreadystatechange", function(){ // check if the DOM is fully loaded if(document.readyState === "complete"){ // remove the listener, to make sure it isn't fired in future document.detachEvent("onreadystatechange", arguments.callee); // The actual handler... } });
或者你可以使用Load事件,如jQuery,这样可以在任何浏览器上运行。这也会导致一个时间延迟,因为它会等待所有的资产被加载。
相信看了本文案例你已经掌握了方法,更多精彩请关注php中文网其它相关文章!
推荐阅读:
The above is the detailed content of How to replace JS with jQuery's Read() method. For more information, please follow other related articles on the PHP Chinese website!

去掉重复并排序的方法:1、使用“Array.from(new Set(arr))”或者“[…new Set(arr)]”语句,去掉数组中的重复元素,返回去重后的新数组;2、利用sort()对去重数组进行排序,语法“去重数组.sort()”。

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于Symbol类型、隐藏属性及全局注册表的相关问题,包括了Symbol类型的描述、Symbol不会隐式转字符串等问题,下面一起来看一下,希望对大家有帮助。

怎么制作文字轮播与图片轮播?大家第一想到的是不是利用js,其实利用纯CSS也能实现文字轮播与图片轮播,下面来看看实现方法,希望对大家有所帮助!

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于对象的构造函数和new操作符,构造函数是所有对象的成员方法中,最早被调用的那个,下面一起来看一下吧,希望对大家有帮助。

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于面向对象的相关问题,包括了属性描述符、数据描述符、存取描述符等等内容,下面一起来看一下,希望对大家有帮助。

方法:1、利用“点击元素对象.unbind("click");”方法,该方法可以移除被选元素的事件处理程序;2、利用“点击元素对象.off("click");”方法,该方法可以移除通过on()方法添加的事件处理程序。

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于BOM操作的相关问题,包括了window对象的常见事件、JavaScript执行机制等等相关内容,下面一起来看一下,希望对大家有帮助。

foreach不是es6的方法。foreach是es3中一个遍历数组的方法,可以调用数组的每个元素,并将元素传给回调函数进行处理,语法“array.forEach(function(当前元素,索引,数组){...})”;该方法不处理空数组。


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

AI Hentai Generator
Generate AI Hentai for free.

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

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.

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),
