[texasx]

может сюда как та, но не получается

<script type="text/javascript">
	//index.php
	$(document).ready(function()
	{

		$(".proc_inv").change(function()
		{
			var id=$(this).val();
			var dataString = 'id='+ id;

			$.ajax
			({
				type: "POST",
				url: "get_proc_sn.php",
				data: dataString,
				cache: false,
				success: function(html)
				{
					$(".proc_sn").html(html);
					$(".proc_model").html(html);
				} 
			});
		});
	});
</script>

<?php
//get_prog_sn.php
include('dbconfig.php');
if($_POST['id'])
{
	$id=$_POST['id'];
	
	$stmt = $DB_con->prepare("SELECT * FROM comp WHERE inv_comp=:id");
	$stmt->execute(array(':id' => $id));
	?><option selected="selected">Select City :</option><?php
	while($row=$stmt->fetch(PDO::FETCH_ASSOC))
	{
		?>
		<option value="<?php echo $row['name_comp']; ?>"><?php echo $row['name_comp']; ?></option>
		<input value="<?php echo $row['sn_comp']; ?>">
		<?php
	}
}
?>