Form <select>

Fandt selv ud af det. ikke sikkert der er rigtigt, men lavede det sådan her:

index siden

<form id="form1" name="form1" method="post" action="send_info.php">
<select name="bygherre" onchange="showUser(this.value)"  style="width:200px;">
<option value="" selected="selected">Bygherre</option>
    <?php
 
  while($sidedate = mysql_fetch_array($valget)) {
     
  echo'<option value="'.$sidedate[id].'">'.$sidedate[navn].'</option>';

  }
 
  ?>
</select>
<label for="kommen"></label>
<input type="text" name="kommen" id="kommen" style="width:200px;" /></td>
<input type="submit" name="button" id="button" value="Start" class="but_send" /></td>
<input type="submit" name="button2" id="button2" value="Stop" class="but_send" /></td>
</form>

Get_user.php siden
<?php
include("URL/TO/connection.php");

$q=$_GET["q"];
$hentsider=mysql_query("SELECT * FROM TABEL_NAVN WHERE caseid = ".$q."");
?>

<?php if($q == 0) {
    echo ''; }else echo '<tr>
<td>
Vælg opgave:<br /></td></tr><select name="sag" style="width:200px;">'; ?>

  <?php
 
  while($sidedate = mysql_fetch_array($hentsider)) {
     
  echo'<option value="'.$sidedate[navn].'">'.$sidedate[navn].'</option>';

  }
 
  ?>
  <?php if($q == 0) {
    echo ''; }else echo '</select>'; ?>