JSFiddle - React, Tailwind, and code Playground

HTML

<select id="sel" size="10" multiple>
    <option>1</option>
    <option>2</option>
    <option>3</option>
    <option>4</option>
    <option>5</option>
    <option>6</option>
    <option>7</option>
    <option>8</option>
    <option>9</option>
    <option>10</option>
    <option>11</option>
    <option>12</option>
    <option>13</option>
    <option>14</option>
</select>
<span id="moveDown">Move Down</span>

JavaScript

$("#moveDown").button().click(function () {
    var select = $("#sel");
    var selItem = $("#sel option:selected")
    var next = selItem.last().next();
    selItem.insertAfter(next);
});