JSFiddle - React, Tailwind, and code Playground

by mahny

HTML

<input type="text" onchange="check(this.value)" onkeyup="check(this.value)">
<div id="msg">（ここにチェック結果を表示する）</div>

JavaScript

function check(v) {
  const msg = (() => {
  	return v ? '入力OKです' : '未入力です';
  })();
  const msgElement = document.getElementById('msg');
  msgElement.innerHTML = `<pre>${msg}
  ---
  v: ${v}
  typeof: ${typeof(v)}
  </pre>`;
}