<script>
function nb(n)
  {
  document.getElementById('esp').innerHTML ='';
  for (i=0;i<n=;i++)
    {
    document.getElementById('esp').innerHTML += 'une fois element';
    }
  }
</script>
 
 
<form name="mc">
 
<select name="nb_choisi size="1">
<option value="2" onSelect="javascript:nb(2);">2</option>
<option value="3" onSelect="javascript:nb(3);">3</option>
<option value="4" onSelect="javascript:nb(4);">4</option>
<option value="5" onSelect="javascript:nb(5);">5</option>
<option value="6" onSelect="javascript:nb(6);">6</option>
<option value="7" onSelect="javascript:nb(7);">7</option>
<option value="8" onSelect="javascript:nb(8);">8</option>
<option value="9" onSelect="javascript:nb(9);">9</option>
<option value="10" onSelect="javascript:nb(10);">10</option>
<option value="11" onSelect="javascript:nb(11);">11</option>
<option value="12" onSelect="javascript:nb(12);">12</option>
<option value="13" onSelect="javascript:nb(13);">13</option>
<option value="14" onSelect="javascript:nb(14);">14</option>
<option value="15" onSelect="javascript:nb(15);">15</option>
</select>
 
<br>
 
<div id = "esp">
Une fois l'élément...
</div>