JSFiddle - React, Tailwind, and code Playground

by huuzoo

HTML

<input type="text" id="form" onchange="inputCheck()">
<div class="frame">入力内容：<span id="output"></span></div>
<div id="alert"></div>

JavaScript

function inputCheck () {
  var form = document.getElementById("form");
  var form_value = form.value;
  
  if (form_value.match(/[0-9]+/g) != form_value ) {
  	document.getElementById('alert').innerHTML = '数値以外はNGです。';
    form.value = '';
  } else {
  	document.getElementById('alert').innerHTML = 'OKです';  
  }
  
  document.getElementById('output').innerHTML = form_value;
}