JSFiddle - React, Tailwind, and code Playground

HTML

<div class="cpNewTemplateDetailsWrap">
    <div class="col-sm-3">
        <label>Course Id</label>
    </div>
    <div class="col-sm-9">
        <input id="courseIdInput" type="text" class="form-control input-lg" placeholder="e.g. CT001" />
    </div>
    <div class="col-sm-3">
        <label>Course Description</label>
    </div>
    <div class="col-sm-9">
        <input id="courseDescInput" type="text" class="form-control input-lg" placeholder="e.g. Cadet Training" />
    </div>
    <div class="col-sm-3">
        <label>Course Duration <small>(Days)</small>
        </label>
    </div>
    <div class="col-sm-9">
        <input id="courseDurationInput" type="number" min="0" class="form-control input-lg" placeholder="5" />
    </div>
    <div class="col-sm-3" id="courseDemandTitle">
        <label>Course Demand</label>
    </div>
    <div class="col-sm-9">
        <input id="courseDemandInput" type="number" min="0" class="form-control input-lg" placeholder="5" />
    </div>
</div>

JavaScript

var myInput = document.querySelectorAll("input[type=number]")[0];
myInput.addEventListener('keypress', function(e) {
  var key = !isNaN(e.charCode) ? e.charCode : e.keyCode;
  function keyAllowed() {
    var keys = [8,9,13,16,17,18,19,20,27,46,48,49,50,
                51,52,53,54,55,56,57,91,92,93];
    if (key && keys.indexOf(key) === -1)
      return false;
    else
      return true;
  }
  if (!keyAllowed())
    e.preventDefault();
}, false);

// Disable pasting of non-numbers
myInput.addEventListener('paste', function(e) {
  var pasteData = e.clipboardData.getData('text/plain');
  if (pasteData.match(/[^0-9]/))
    e.preventDefault();
}, false);