「React入門」selectドロップダウンメニューのonchangeイベントを使うサンプル
書式
handleChange(event){ some code}
handleSubmit(event) {some code}
<select value={this.state.value} onChange={this.handleChange}>
使用例
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>React サンプル</title>
<script src="/react/16.4.0/umd/react.development.js"></script>
<script src="/react-dom/16.4.0/umd/react-dom.development.js"></script>
<script src="/babel-standalone/6.26.0/babel.min.js"></script>
</head>
<body>
<div id="arkgame"></div>
<script type="text/babel">
class CftForm extends React.Component {
constructor(props) {
super(props);
this.state = {value: 'default value'};
this.handleChange = this.handleChange.bind(this);
this.handleSubmit = this.handleSubmit.bind(this);
}
handleChange(event) {
this.setState({value: event.target.value});
}
handleSubmit(event) {
alert('選択した都市: ' + this.state.value);
event.preventDefault();
}
render() {
return (
<form onSubmit={this.handleSubmit}>
<label>
都市を選択してください
<select value={this.state.value} onChange={this.handleChange}>
<option value="tokyo">東京</option>
<option value="oosaka">大阪</option>
<option value="fukuoka">福岡</option>
<option value="kawasaki">川崎</option>
</select>
</label>
<input type="submit" value="選択" />
</form>
);
}
}
ReactDOM.render(
<CftForm />,
document.getElementById('arkgame')
);
</script>
</body>
</html>