JSFiddle - React, Tailwind, and code Playground

HTML

<select id="myselect-name" my_attribute="1" class="myclass">
    <option>1</option>
    <option>2</option>
    <option>3</option>
</select>

JavaScript

$('.myclass').change(function() {
	$(this).attr('my_attribute', $(this).val());
	alert($(this).attr('my_attribute'));
});