JSFiddle - React, Tailwind, and code Playground

HTML

<select id="foo">
    <option selected="selected" value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
    <option value="4">4</option>
    <option value="5">5</option>
    <option value="6">6</option>
    <option value="7">7</option>
</select>
<input type="button" value="next" onclick="suivant()" />

JavaScript

function suivant() {
 
    myopts = document.getElementById('foo').options
    var i = -1;
    while (myopts[++i]) {
        alert(myopts[i].value)
        if (myopts[i].selected && myopts[i + 1]) {
            myopts[i + 1].selected = "selected"
            break;
        }
    }

}