alertHelloWorld.md

order	title
0	zh-CN en-US helloWord helloWord

zh-CN

这就是个helloWorld

en-US

This is helloWorld

let handleClick = () => {
  alert("hello world");
};

ReactDOM.render(
  <div>
    <button type="primary" onClick={handleClick}>Hello World</button>
  </div>
, mountNode);