Here are some quick differences/similarities between React.js and React-Native:
2. In React-Native, the tags like <View>, <Text> are used very frequently and React.js, on the other hand, uses web html tags like <div> <h1> <h2>. There are only synonyms in dictionary of web/mobile developments.
3. For React.js, you need DOM for path rendering of html tags whereas for mobile application, React-Native uses AppRegistry to register your app.
If you are interested to learn React Js, check out this React Js Training Course by Intellipaat.
Also, check out this video for more similarities and differences between React.js and React-Native: