JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>
<title>Untitled Document</title>
<script language="javascript">
function checkInput(ob) {
  var invalidChars = /[^0-9]/gi
  if(invalidChars.test(ob.value)) {
            ob.value = ob.value.replace(invalidChars,"");
      }
}
</script>
</head>

<body>
    <input type="text" onkeyup="checkInput(this)"/>
</body>
</html>