probleme selection option (JS pur)

by LorenzoFR

HTML

<link rel="stylesheet" href="http://knacss.com/css/knacss.css">
<div class="txtcenter">
    <select id="select1">
        <option value="1" label="texte 1">texte 1</option>
        <option value="2" label="texte 2">texte 2</option>
        <option value="3" label="texte 3">texte 3</option>
        <option value="4" label="texte 4">texte 4</option>
        <option value="5" label="texte 5">texte 5</option>
    </select>
</div>

CSS

select {
    font-size: 150%;
    background-color: #ffffaa;
}

JavaScript

var select = document.getElementById('select1');
var totalOptions = select.length;

function interval() {
		var idCourant = select.selectedIndex;
		select.options[idCourant].removeAttribute('selected');

		idCourant += 1;
		if (idCourant >= totalOptions) {
				idCourant = 0;
		}
		select.options[idCourant].setAttribute('selected', 'selected');
}
var idInterval = setInterval(interval, 500);



$(window).on('keydown', function(ev) {
		if (ev.which === 27) {
				clearInterval(idInterval);
		}
});