Answers for "select2 on select"

select2.org events

$('#mySelect2').on('select2:select', function (e) {
    var data = e.params.data;
    console.log(data);
});

select2 multi select

######## In your HTML:
<select class="js-example-basic-multiple" name="states[]" multiple="multiple">
  <option value="AL">Alabama</option>
    ...
  <option value="WY">Wyoming</option>
</select>

####### In your Javascript (external .js resource or <script> tag):
$(document).ready(function() {
    $('.js-example-basic-multiple').select2();
});

######### Get Selected values
$('.js-example-basic-multiple').select2('val')

######## Pre select values on page loads
 $('.js-example-basic-multiple').val(['AL', 'WY']).trigger('change');

select2

<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/select2.min.css" rel="stylesheet" />
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/select2.min.js"></script>

select2

$(".js-example-basic-multiple-limit").select2({
  maximumSelectionLength: 3
});

select2

$('.js-example-basic-single').select2({
  placeholder: 'Select an option'
});