DOM No Response to Keyboard Event

Register onKeyDownListener on HTML Element

<!DOCTYPE html>
<html>
<head>
<script src="../build/react.js"></script>
<script src="../build/react-dom.js"></script>
<script src="../build/browser.min.js"></script>
</head>
<body>
<div id="app"></div>
<script type="text/babel">
class App extends React.Component {
handleKeyDown(event) {
console.log('handling a key press');
}
render() {
return (
<div onKeyDown={this.handleKeyDown}>
here!
</div>
);
}
}
ReactDOM.render(<App />, document.getElementById('app'));
</script>
</body>
</html>

There are NO response here. You press any thing and there is NO response. It’s doesn’t matter you mouse focus on div or not.

Add tabIndex

Try add this,

<div onKeyDown={this.handleKeyDown}
tabIndex={0}>
here!
</div>

tabIndex={0} and we are done!

Another interesting thing is that the div element will gain a

#app:focus {
outline: -webkit-focus-ring-color auto 5px;
}

In the same time you set a tabIndex attribute. That’s actually an indicator that you can make keyboard event on this. Use this to surpress:

<div onKeyPress={this.handleKeyDown}
tabIndex={0}
style={{outline: 'none'}}>
here!
</div>

Done!

Reason

StackOverflow - React not responding to key down event

it’s the only way elements beside links and form elements can receive keyboard focus and thus key presses. It’s set to zero so that it doesn’t override the native tab order.

More interesting

If you use onKeyPress listener, you will miss the Esc key press event.

onKeyPress={this.handleKeyDown}

Press Esc on this will trigger nothing. Try onKeyUp or onKeyDown instead.

Reason

keydownwill mimic native behaviour - at least on Windows where pressing ESC or Return in a dialog will trigger the action before the key is released.

Ref