<!-- Partie HTML -->
<table>
  <tr>
    <td>
      <select id="LstSource" style="font-family:verdana; font-size:10; width:120;" size="6" ondblclick="Ajouter();">
        <option>Angleterre</option>
        <option>Espagne</option>
        <option>France</option>
        <option>Portugal</option>
        <option>Italie</option>
      </select>
    </td>
    <td>
      <input type="button" style="font-family:verdana; font-size:10;" value="» Ajouter »" onclick="Ajouter();">
      <br>
      <input type="button" style="font-family:verdana; font-size:10;" value="« Retirer «" onclick="Supprimer();">
    </td>
    <td>
      <select id="LstCible" style="font-family:verdana; font-size:10; width:120;" size="6" ondblclick="Supprimer();">
      </select>
    </td>
  </tr>
</table>

<!-- Partie JavaScript -->
<script language="javascript">
   var NbSource = 5;
   var NbCible = 0;

   function Ajouter(){
     var NbEle = -1;
     var TxtEle = "";
     for(i = 0; i < document.all("LstSource").length; i++){
       if (document.all("LstSource").options[i].selected){
         NbEle = i;
         TxtEle = document.all("LstSource").options[i].text;
       }
     }


     if (NbSource != 0 && NbEle != -1){
       document.all("LstSource").options[NbEle] = null;
       document.all("LstCible").options[NbCible] = new Option(TxtEle);
       NbCible = NbCible + 1;
       NbSource = NbSource - 1;
     }
   }

   function Supprimer(){
     var NbEle = -1;
     var TxtEle = "";
     for(i = 0; i < document.all("LstCible").length; i++){
       if (document.all("LstCible").options[i].selected){
         NbEle = i;
         TxtEle = document.all("LstCible").options[i].text;
       }
     }

     if (NbCible != 0 && NbEle != -1){
       document.all("LstCible").options[NbEle] = null;
       document.all("LstSource").options[NbSource] = new Option(TxtEle);
       NbCible = NbCible - 1;
       NbSource = NbSource + 1;
     }
   }
</script>