Sì per forza, sono dei menu a discesa non li indirizzi con .value=

codice:
<script type="text/javascript">
  
function aggiorna() {
var year=<?php echo ($anno)?$anno:'new Date().getFullYear()'; ?>;
for(var i=0; i<document.getElementById("year").options.length;i++){if(document.getElementById("year").options[i].text==year){document.getElementById("year").selectedIndex=i;break;};}

var month=<?php echo ('$mese')?$mese:'new Date().getMonth()'; ?>;
for(var i=0; i<document.getElementById("month").options.length;i++){if(document.getElementById("month").options[i].value==month){document.getElementById("month").selectedIndex=i;break;};}

var day=<?php echo ($giorno)?$giorno:'(new Date().getDate())'; ?>;
for(var i=0; i<document.getElementById("day").options.length;i++){if(document.getElementById("day").options[i].text==day){document.getElementById("day").selectedIndex=i;break;};}

var hour='<?php echo $ora;?>';
for(var i=0; i<document.getElementById("hour").options.length;i++){if(document.getElementById("hour").options[i].text==hour){document.getElementById("hour").selectedIndex=i;break;};}
}

 </script>






<form method="post" action="test.php">
  


  <table width="198" border="0">
    <tr>
      <td width="53"><div align="center" class="Stile1">Anno</div></td>
      <td width="129"><select id="year" name="Anno">
        <option>2010</option>

        <option>2011</option>
      </select></td>
    </tr>
    <tr>
      <td><div align="center" class="Stile1">Mese</div></td>
      <td><select id="month" name="Mese">
        <option value="0">Gennaio</option>

        <option value="1">Febbraio</option>
        <option value="2">Marzo</option>
        <option value="3">Aprile</option>
        <option value="4">Maggio</option>
        <option value="5">Giugno</option>
        <option value="6">Luglio</option>

        <option value="7">Agosto</option>
        <option value="8">Settembre</option>
        <option value="9">Ottobre</option>
        <option value="10">Novembre</option>
        <option value="11">Dicembre</option>
     
      </select></td>

    </tr>
    <tr>
      <td><div align="center" class="Stile1">Giorno</div></td>
      <td><select id="day" name="Giorno">
        <option>1</option>
        <option>2</option>
        <option>3</option>

        <option>4</option>
        <option>5</option>
        <option>6</option>
        <option>7</option>
        <option>8</option>
        <option>9</option>

        <option>10</option>
        <option>11</option>
        <option>12</option>
        <option>13</option>
        <option>14</option>
        <option>15</option>

        <option>16</option>
        <option>17</option>
        <option>18</option>
        <option>19</option>
        <option>20</option>
        <option>21</option>

        <option>22</option>
        <option>23</option>
        <option>24</option>
        <option>25</option>
        <option>26</option>
        <option>27</option>

        <option>28</option>
        <option>29</option>
        <option>30</option>
        <option>31</option>
      </select></td>
    </tr>
    <tr>

      <td><div align="center" class="Stile1">Ora</div></td>
      <td><select id="hour" name="ora">
        <option>00.00</option>
        <option>01.00</option>
        <option>02.00</option>
        <option>03.00</option>

        <option>04.00</option>
        <option>05.00</option>
        <option>06.00</option>
        <option>07.00</option>
        <option>08.00</option>
        <option>09.00</option>

        <option>10.00</option>
        <option>11.00</option>
        <option>12.00</option>
        <option>13.00</option>
        <option>14.00</option>
        <option>15.00</option>

        <option>16.00</option>
        <option>17.00</option>
        <option>18.00</option>
        <option>19.00</option>
        <option>20.00</option>
        <option>21.00</option>

        <option>22.00</option>
        <option>23.00</option>
        <option></option>
      </select></td>
    </tr>
  </table>





<script>aggiorna();</script>