JSFiddle - React, Tailwind, and code Playground

by Mukesh Yadav

HTML

<input onkeydown="javascript:return isRequired(this)" />
<script>
  function isRequired(e) {
    var num = e.value;
    var p0 = num[0] || 0;
    var p1 = num[1] || 0;
    var p2 = num[2] || 0;
    var p3 = num[3];
    var p4 = num[4] || 0;

    isValid = false;
    if (num.length < 6 && !isNaN(parseInt(p0 + p1 + p2))) {
      isValid = true;
    }

    if (p3 && p3.length == 1) {
      if (p3 == '.' || p3 == ',') {
        isValid = true;
        if (p4 && p4.length == 1) {
          if (!isNaN(parseInt(p4))) {
            isValid = true;
          } else {
            isValid = false;
          }
        }
      } else {
        isValid = false;
      }
    }
    console.log(isValid);
    return isValid;
  }
  console.log(isRequired('123'));
  console.log(isRequired('123.1'));
  console.log(isRequired('123.'));
  console.log(isRequired('123,1'));
  console.log(isRequired('123,'));
  console.log(isRequired('123123'));

</script>