multiple select controle (Opgelost)

echo "<tr class='row2'><td width='10'></td><td>Medewerker(s) :</td><td colspan='3'>";
echo "<select name='medewerker[]' multiple='multiple'>";

$sql = "SELECT * FROM gebruiker ORDER BY medewerker ASC";
$resultaat = mysql_query($sql) or die(mysql_error());

$rows = mysql_num_rows($resultaat); 

if (isset($_POST['medewerker']))
{
	for($a = 0; $record = mysql_fetch_assoc($resultaat); $a++)
	{
		if (($_POST['medewerker'][$a]) == ($record['medewerker']))
		{
			echo "<option value='" . $_POST['medewerker'][$a] . "' selected>" . $_POST['medewerker'][$a] . "</a>";
		}
		else
		{
			echo "<option value='" . $record['medewerker'] . "'>" . $record['medewerker'] . "</option>";
		}		
	}
}

echo "</select>";

echo "<tr class='row2'><td width='10'></td><td>Medewerker(s) :</td><td colspan='3'>";
echo "<select name='medewerker[]' multiple='multiple'>";
 
$sql = "SELECT * FROM gebruiker ORDER BY medewerker ASC";
$resultaat = mysql_query($sql) or die(mysql_error());
 
$rows = mysql_num_rows($resultaat); 
 
if (isset($_POST['medewerker']))
{
	for($a = 0; $record = mysql_fetch_assoc($resultaat); $a++)
	{
		if (($_POST['medewerker'][$a]) == ($record['medewerker']))
		{
			echo "<option value='" . $_POST['medewerker'][$a] . "' selected>" . $_POST['medewerker'][$a] . "</a>";
		}
		else
		{
			echo "<option value='" . $record['medewerker'] . "'>" . $record['medewerker'] . "</option>";
		}		
	}
}
 
echo "</select>";

<?php 
echo '
  <tr class="row2">
    <td width="10"></td>
    <td>Medewerker(s) :</td>
    <td colspan="3">
      <select name="medewerker[]" multiple="multiple">';

$sql = "SELECT id, naam FROM gebruiker ORDER BY medewerker ASC";
$resultaat = mysql_query($sql) or die(mysql_error());
while($assoc = mysql_fetch_assoc($resultaat)){
      echo '<option value="'.$assoc['id'].'" '.(isset($_POST['medewerker']) && in_array($assoc['id'], $_POST['medewerker']) ? 'selected="selected"' : '').'>'.$assoc['naam'].'</option>';
}
echo '</select>';
?>

<?php 
echo '
  <tr class="row2">
    <td width="10"></td>
    <td>Medewerker(s) :</td>
    <td colspan="3">
      <select name="medewerker[]" multiple="multiple">';
 
$sql = "SELECT id, naam FROM gebruiker ORDER BY medewerker ASC";
$resultaat = mysql_query($sql) or die(mysql_error());
while($assoc = mysql_fetch_assoc($resultaat)){
      echo '<option value="'.$assoc['id'].'" '.(isset($_POST['medewerker']) && in_array($assoc['id'], $_POST['medewerker']) ? 'selected="selected"' : '').'>'.$assoc['naam'].'</option>';
}
echo '</select>';
?>