Update README.md

Author: cheton

README.md

@@ -43,7 +43,7 @@ Then, include these scripts into your html file:
 ```
 
 Use <b>&lt;ReactSortable /&gt;</b> instead of <b>&lt;Sortable /&gt;</b> in your JSX code since the Sortable library will export a <b>window.Sortable</b> object if you're running JSX code directly in the browser. For example:
-```jsx
+```js
 <ReactSortable
     tag="ul"
     onChange={(order) =>
@@ -56,7 +56,7 @@ Use <b>&lt;ReactSortable /&gt;</b> instead of <b>&lt;Sortable /&gt;</b> in your
 
 ## Usage
 File: sortable-list.jsx
-```jsx
+```js
 import React from 'react';
 import Sortable from 'react-sortablejs';
 
@@ -111,7 +111,7 @@ export default SortableList;
 ```
 
 File: index.jsx
-```jsx
+```js
 import React from 'react';
 import ReactDOM from 'react-dom';
 import SortableList from './sortable-list';