JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<body>
    <input type="button" id="event-city-add-submit" class="add:event-citychecklist:event-city-add button category-add-submit" value="Add New Category" tabindex="3" />
    <ul id="result"></ul>
</body>
</html>

JavaScript

$(function(){
    w = function(o) {
         $('#result').append( '<li>' + o + '</li>' );
    };
    i = $('input');
    w( i.is('[class^="add:event-citychecklist:"]') );
});