JSFiddle - React, Tailwind, and code Playground

by Tamil

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/ui-lightness/jquery-ui.css">
<select id="select1" name="indication_subject[]">
  <option value="" selected="selected">a </option>
  <option value="1"> Accounting</option>
  <option value="2"> Afrikaans</option>
  <option value="3"> Applied Information and Communication Technology</option>
  <option value="4"> Arabic</option>
  <option value="5"> Art and Design</option>
  <option value="6"> Biology</option>
  <option value="7"> Business Studies</option>
</select>

<select id="select2" name="indication_subject[]">
  <option value="" selected="selected">a </option>
  <option value="1"> Accounting</option>
  <option value="2"> Afrikaans</option>
  <option value="3"> Applied Information and Communication Technology</option>
  <option value="4"> Arabic</option>
  <option value="5"> Art and Design</option>
  <option value="6"> Biology</option>
  <option value="7"> Business Studies</option>
</select>

<select id="select3" name="indication_subject[]">
  <option value="" selected="selected">a </option>
  <option value="1"> Accounting</option>
  <option value="2"> Afrikaans</option>
  <option value="3"> Applied Information and Communication Technology</option>
  <option value="4"> Arabic</option>
  <option value="5"> Art and Design</option>
  <option value="6"> Biology</option>
  <option value="7"> Business Studies</option>
</select>

JavaScript

$(document).ready(function(){  
  $("select").change(function() {   
    $("select").not(this).find("option[value="+ $(this).val() + "]").attr('disabled', true);
  }); 
});