一、ReactJS简介
React 是近期非常热门的一个前端开发框架。React 起源于 Facebook 的内部项目,因为该公司对市场上所有 JavaScript MVC 框架,都不满意,就决定自己写一套,用来架设 Instagram 的网站。做出来以后,发现这套东西很好用,就在2013年5月开源了。由于 React 的设计思想极其独特,属于革命性创新,性能出众,代码逻辑却非常简单。所以,越来越多的人开始关注和使用,认为它可能是将来 Web 开发的主流工具。
ReactJS官网地址:http://facebook.github.io/react/
Github地址:https://github.com/facebook/react
ReactJS中文地址:http://reactjs.cn/react/docs/getting-started.html
React是什么?
React是由工作在Facebook的优秀程序员开发出来的用于开发用户交互界面的JS库。其源码由Facebook和社区优秀的程序员维护,因此其背后有着非常强大的技术团队给予技术支持。React带来了很多新的东西,例如组件化、JSX、虚拟DOM等。其提供的虚拟DOM使得我们渲染组件呈现非常之快,让我们从频繁操作DOM的繁重工作之中解脱。了解React的人都知道,它做的工作更多偏重于MVC中的V层,结合其它如Flux等一起,你可以非常容易构建强大的应用。
二、ReactJS特点
1,虚拟DOM
通过DOM diff算法,只会更新有差异化的部分,不用渲染整个页面,从而提高效率
2,组件化
把页面分成若干个组件,组件中包含逻辑结构和样式
组件只包含自身逻辑,更新组件的时候可以预测,利于维护
页面拆分多个组件,可以做到重用
3,单向数据流
数据是从顶层组件传递到子组件中
数据可控
三、入门React 编写 Hello,world 首先了解下什么是JSX
React的核心机制之一就是虚拟DOM:可以在内存中创建的虚拟DOM元素。React利用虚拟DOM来减少对实际DOM的操作从而提升性能。类似于真实的原生DOM,虚拟DOM也可以通过JavaScript来创建,例如:
var child1 = React.createElement('li', null, 'First Text Content'); var child2 = React.createElement('li', null, 'Second Text Content'); var root2 = React.createElement('ul', { className: 'my-list' }, child1, child2); React.render( <div>{root2}</div>, document.getElementById('container5') );
使用这样的机制,我们完全可以用JavaScript构建完整的界面DOM树,正如我们可以用JavaScript创建真实DOM。但这样的代码可读性并不好,于是React发明了JSX,利用我们熟悉的HTML语法来创建虚拟DOM:
var root =( <ul className="my-list"> <li>First Text Content</li> <li>Second Text Content</li> </ul> ); React.render( <div>{root}</div>, document.getElementById('container6') );
四、React 编写Hello,world 入门的5种方式
第1种方式
<div id="example1"></div> <script type="text/jsx"> React.render( //直接html <h1 id="hellow-直接-html-world">1 hellow 直接 html world </h1>, document.getElementById('example1') ); </script>
第2种方式
<div id="example2"></div> <script type="text/jsx"> React.render( //直接创建元素 React.createElement('h1', {className:'classN2'}, '2 Hello, 直接创建元素 world!'), document.getElementById('example2') ); </script>
第3种方式
<div id="example3"></div> <script type="text/jsx"> var CreateEl=React.createClass({ render:function(){ // return <h1 id="hellow-组件-创建-html-world">hellow 组件 创建 html world </h1> //有无括号均可 return (<h1 id="hellow-组件-创建-html-world">3 hellow 组件 创建 html world </h1>); } }); React.render( //组件方式创建元素 <CreateEl/>, //或者双括号 <CreateEl></CreateEl> document.getElementById('example3') ); </script>
第4种方式
<div id="example4"></div> <script type="text/jsx"> var JsxCreateEl=React.createClass({ // 直接 jsx 方式 创建 render:function(){ return ( React.createElement('h1', {className: "classN4"},"4 Hello, 直接 jsx 方式 创建 world! ") ) } }); React.render( //组件方式创建元素 React.createElement(JsxCreateEl, null), document.getElementById('example4') ); </script>
第5种方式
<div id="example5"></div> <script type="text/jsx"> var Hello=React.createClass({ // 模板 Hello render:function(){ return (<span>{this.props.data}</span>) } }); var World=React.createClass({ // 模板 world render:function(){ return (<span> 和 World 模板拼接</span>) } }); React.render( // 2个 模板 组件方式创建元素 <h1 className="classN5" > <Hello data='5 hello' /> <World /> </h1>, document.getElementById('example5') ); </script>
五、上结果图
附上代码:
无标题文档 <div id="example5"></div> <script type="text/jsx"> var Hello=React.createClass({ // 模板 Hello render:function(){ return (<span>{this.props.data}</span>) } }); var World=React.createClass({ // 模板 world render:function(){ return (<span> 和 World 模板拼接</span>) } }); React.render( // 2个 模板 组件方式创建元素 <h1 className="classN5" > <Hello data='5 hello' /> <World /> </h1>, document.getElementById('example5') ); </script>
下面给大家补充点知识:
React 术语
React Elements
代表 HTML 元素的 JavaScript 对象。 这些 JavaScript 对象最后被编译成对应的 HTML 元素。
Components
封装 React Elements, 包含一个或者多个 React Elements。 Components 用于创建可以复用的 UI 模块,例如 分页,侧栏导航等。
JSX
JSX 是 React 定义的一种 JavaScript 语法扩展,类似于 XML 。 JSX 是可选的, 我们完全可以使用 JavaScript 来编写 React 应用, 不过 JSX 提供了一套更为简便的方式来写 React 应用。
Virtual DOM
Virtual DOM 是一个模拟 DOM 树的 JavaScript 对象。 React 使用 Virtual DOM 来渲染 UI, 同时监听 Virtual DOM 上数据的变化并自动迁移这些变化到 UI 上。

Detailed explanation of JavaScript string replacement method and FAQ This article will explore two ways to replace string characters in JavaScript: internal JavaScript code and internal HTML for web pages. Replace string inside JavaScript code The most direct way is to use the replace() method: str = str.replace("find","replace"); This method replaces only the first match. To replace all matches, use a regular expression and add the global flag g: str = str.replace(/fi

This tutorial shows you how to integrate a custom Google Search API into your blog or website, offering a more refined search experience than standard WordPress theme search functions. It's surprisingly easy! You'll be able to restrict searches to y

So here you are, ready to learn all about this thing called AJAX. But, what exactly is it? The term AJAX refers to a loose grouping of technologies that are used to create dynamic, interactive web content. The term AJAX, originally coined by Jesse J

This article series was rewritten in mid 2017 with up-to-date information and fresh examples. In this JSON example, we will look at how we can store simple values in a file using JSON format. Using the key-value pair notation, we can store any kind

Enhance Your Code Presentation: 10 Syntax Highlighters for Developers Sharing code snippets on your website or blog is a common practice for developers. Choosing the right syntax highlighter can significantly improve readability and visual appeal. T

Leverage jQuery for Effortless Web Page Layouts: 8 Essential Plugins jQuery simplifies web page layout significantly. This article highlights eight powerful jQuery plugins that streamline the process, particularly useful for manual website creation

This article presents a curated selection of over 10 tutorials on JavaScript and jQuery Model-View-Controller (MVC) frameworks, perfect for boosting your web development skills in the new year. These tutorials cover a range of topics, from foundatio

Core points This in JavaScript usually refers to an object that "owns" the method, but it depends on how the function is called. When there is no current object, this refers to the global object. In a web browser, it is represented by window. When calling a function, this maintains the global object; but when calling an object constructor or any of its methods, this refers to an instance of the object. You can change the context of this using methods such as call(), apply(), and bind(). These methods call the function using the given this value and parameters. JavaScript is an excellent programming language. A few years ago, this sentence was


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

Dreamweaver CS6
Visual web development tools

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

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),

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment
