import?React?from?'react';
import?ReactDOM?from?'react-dom';
import?App?from?'./App';

ReactDOM.render(<App?/>,?document.getElementById('root'));

import?React,?{Component}?from?'react';

class?App?extends?Component?{
??render()?{
????return?(
??????<div>123</div>
????);
??}
}

export?default?App;

點面頁面空白處的氐警報：

Uncaught TypeError: Cannot read property 'nodeName' of null

? ? at HTMLDocument.onMouseClick