djonA,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<script>
window.addEventListener('DOMContentLoaded', function() {
var nodes = document.querySelectorAll('.alliki'),
select = document.querySelector('select');
select.addEventListener('mousedown', function create() {
[].forEach.call( nodes, function(span) {
var val = span.innerHTML;
var option = new Option(val, val);
select.appendChild(option)
});
select.removeEventListener('mousedown',create)
});
});
</script>
</head>
<body>
<span class="alliki">1</span>
<span class="alliki">2</span>
<span class="alliki">3</span>
<span class="alliki">4</span>
<select id="select" >
</select>
</body>
</html>