JSFiddle - React, Tailwind, and code Playground

HTML

<div class="content">       
    <div class="tlcontent"> 
        <div class="sideon" id="sideline0"> 
            somethings
        </div>

        <div class="trackon" id="trackline0">
            somethings
        </div

        <div class="sideon" id="sideline1"> 
            somethings
        </div

        <div class="sideon" id="sideline2">
            somethings
        </div            
    </div>
</div>

JavaScript

$(function(){
    alert($('#sideline0').next().attr('class'));
});