JSFiddle - React, Tailwind, and code Playground

by Сергей Тарасевич

HTML

<div class="track" data-track="123">track 123</div>
<div class="dop_tracks">
    <div class="track" data-track="124">track 124</div>
    <div class="track" data-track="125">track 125</div>
</div>

JavaScript

$(document).on('click', '[data-track]', function (e) {

    var a = '',
        b = $(this).data('track'),
        c = '',
        d = 0;

    $('[data-track]').each(function (indx) {
        a = $(this).data('track');
        if (d == 1) {
            d = 0;
            c = a;
        }
        if (b == a && d == 0) {
            d = 1;
        }
    });

    alert(c);

});