ReactJS是一个用于构建UI组件层次结构的框架。每个组件都有状态和道具。数据通过道具从顶层流向底层组件。在顶级组件中使用事件处理程序更新状态。

React native使用React框架为移动应用程序构建组件。React native为iOS和Android平台提供了一组基本的组件。React Native中的一些组件是Navigator, TabBar, Text, TextInput, View, ScrollView。这些组件内部使用原生iOS UIKit和Android UI组件。React native还允许使用NativeModules，其中用iOS的objective - c和Android的Java编写的代码可以在JavaScript中使用。

注意:React Native作为一个框架，允许以类似HTML和CSS的语法开发移动应用程序。原生组件在原生开发中有效地取代了HTML。

为了回应上面@poshest的评论，这里有一个React Native版本的时钟代码，之前在React中发布(抱歉，我无法直接评论这部分，否则我会在那里添加代码):

React Native代码示例

import { AppRegistry } from 'react-native';
import React, { Component } from 'react';
import { View, Text, StyleSheet } from 'react-native';

class Clock extends Component {
  constructor(props) {
    super(props);
    this.state = { date: new Date() };
  }

  componentDidMount() {
    this.timerID = setInterval(
      () => this.tick(),
      1000
    );
  }

  componentWillUnmount() {
    clearInterval(this.timerID);
  }

  tick() {
    this.setState({
      date: new Date()
    });
  }

  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.sectionTitle}>Hello, world!</Text>
        <Text style={styles.sectionDescription}>It is {this.state.date.toLocaleTimeString()}.</Text>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    backgroundColor: 'white',
    flex: 1,
    justifyContent: 'center',
  },
  sectionTitle: {
    fontSize: 24,
    fontWeight: '600',
    color: 'black',
    alignSelf: 'center',
  },
  sectionDescription: {
    marginTop: 8,
    fontSize: 18,
    fontWeight: '400',
    color: 'darkgrey',
    alignSelf: 'center',
  },
});

AppRegistry.registerComponent("clock", () => Clock);

注意，样式完全是我的选择，并不寻求直接复制在React代码中使用的<h1>和<h2>标记。

总结:React.js用于Web开发，而React-Native用于移动应用程序开发

REACT是一个Javascript库，用于构建像Facebook这样的大型/小型界面web应用程序。

REACT NATIVE是一个Javascript框架，用于开发Android、IOS和Windows Phone上的原生移动应用程序。

两者都是由Facebook开源的。

在Reactjs中，虚拟DOM用于在Reactjs中渲染浏览器代码，而在React Native中，本地api用于渲染移动设备中的组件。

用Reactjs开发的应用程序在UI中渲染HTML，而React Native使用JSX来渲染UI，这只是javascript。

我们无法准确地比较它们。用例中存在差异。

(2018更新)

反应

React的主要关注点是Web开发。

React’s virtual DOM is faster than the conventional full refresh model, since the virtual DOM refreshes only parts of the page. You can reuse code components in React, saving you a lot of time. (You can in React Native too.) As a business: The rendering of your pages completely, from the server to the browser will improve the SEO of your web app. It improves the debugging speed making your developer’s life easier. You can use hybrid mobile app development, like Cordova or Ionic, to build mobile apps with React, but is more efficiently building mobile apps with React Native from many points.

反应本地

React的扩展，针对移动开发。

Its main focus is all about Mobile User Interfaces. iOS & Android are covered. Reusable React Native UI components & modules allow hybrid apps to render natively. No need to overhaul your old app. All you have to do is add React Native UI components into your existing app’s code, without having to rewrite. Doesn't use HTML to render the app. Provides alternative components that work in a similar way, so it wouldn't be hard to understand them. Because your code doesn’t get rendered in an HTML page, this also means you won’t be able to reuse any libraries you previously used with React that renders any kind of HTML, SVG or Canvas. React Native is not made from web elements and can’t be styled in the same way. Goodbye CSS Animations!

希望我帮到你了:)