Select2 callback function

used for stackoverflow: http://stackoverflow.com/questions/36427264/how-to-add-custom-callback-to-jquery-plugin

by Bhumika107

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.2/js/select2.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.2/css/select2.min.css">
<select class="select2">
  <option value="volvo"><li>Volvo</li></option>
  <option value="saab"><li>Saab</li></option>
  <option value="mercedes"><li>Mercedes</li></option>
  <option value="audi"><li>Audi</li></option>
</select>

JavaScript

$('.select2').select2();
$('.select2').on('click', function(li_element){
    $(this).siblings(".select2-container--open").find(".select2-results__option").each(function(index,el) {
        console.log($(el).text());
        $(el).addClass('bg-' + $(el).text());
    });
});