JSFiddle - React, Tailwind, and code Playground

by Mubasshir Pawle

HTML

<select class="a1">
  <option value="">Select</option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
</select>
<select class="a1">
  <option value="">Select</option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
</select>
<select class="a1">
  <option value="">Select</option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
</select>

JavaScript

$('body').on('change', '.a1', function() {
  var This = $(this);
  var currentVal = This.val();
  //check if exis
  var allVals = [];
  $('.a1').not(This).each(function() {
    if ($(this).val()) {
      allVals.push($(this).val());
    }
  });
  if (allVals.indexOf(currentVal) > -1) {
    This.val('');
  }
});