<script type="text/javascript">
<!--
function MM_jumpMenu(targ,selObj,restore){ //v3.0
  eval(targ+".location='"+selObj.options[selObj.selectedIndex].value+"'");
  if (restore) selObj.selectedIndex=0;
}
//-->
</script>
<form id="form1" name="form1" method="post" action="">
  Marka :
  <select name="jumpMenu" id="jumpMenu" onchange="MM_jumpMenu('parent',this,0)">
  <?php $sql=mysql_query("select * from marka order by ad asc");
  while($marka=mysql_fetch_array($sql)){
  
  ?>
    <option value="urun.php?id=<?php echo $marka['id']?>"><?php echo $marka['marka']?></option>
    <?php } ?>
  </select>
  <label>
    Ürün :
    <select name="select" id="select">
    <?php
    if(isset($_GET['id'])){
		$sql2=mysql_query("select * from urun where marka='".$_GET['id']."'");
		while($row=mysql_fetch_array($sql2))
		?>
		 <option value="<?php echo $row['id']?>"><?php echo $row['urun']?></option>
	<?php }
  }else{
     ?>
      <option value="0">Marka Seçiniz.</option>
      <?php } ?>
    </select>
  </label>
</form>