JSFiddle - React, Tailwind, and code Playground

HTML

<div id="structuresWrap">
    <select>
        <option>1</option>
        <option>2</option>
        <option>3</option>
        <option>4</option>
        <option>5</option>
        <option>6</option>
    </select>
    <select>
        <option>a</option>
        <option>b</option>
        <option>c</option>
        <option>d</option>
        <option>e</option>
        <option>f</option>
    </select>
     <select>
        <option>a</option>
        <option>b</option>
        <option>c</option>
        <option>d</option>
        <option>e</option>
        <option>f</option>
    </select>
     <select>
        <option>a</option>
        <option>b</option>
        <option>c</option>
        <option>d</option>
        <option>e</option>
        <option>f</option>
    </select>
     <select>
        <option>a</option>
        <option>b</option>
        <option>c</option>
        <option>d</option>
        <option>e</option>
        <option>f</option>
    </select>
<span id="res"></span>

</div>

JavaScript

$(function () {
    $('#structuresWrap').on('change', '> select', function (idx, vlr) {
        if ($('#structuresWrap > select').index(this) == 0) {
            alert('premier');
        } else {
            alert('Pas le premier !!!')
        }
    });
})