Change <select> values

programming
1

Hi,
I am trying to make a <select> box change its values based on the users input to another drop down.
I want to populate them from my database, the initial one is coded as follows:

include 'library/config.php';
		include 'library/opendb.php';
		$query  = "SELECT brand FROM brand_data ORDER BY brand";
		$result = mysql_query($query) or die('Error : ' . mysql_error()); 
		
		// create the brand list 
		$brandmenu =  '<select name="brand" class="txtBox" onChange="regionMenu(this.value)"><option value="">--SELECT--</option>';
		while($row = mysql_fetch_array($result, MYSQL_NUM))
		{
		list($title) = $row;
		$brandmenu .= "<option value=\"$title\">$title</option>
";
		}
	
		$brandmenu .= '</select>';
		echo $brandmenu;
		
		include 'library/closedb.php';
		?>

As you can see, this has an ‘onClick’ option, as my guess is that you call some javascript which would then perform the PHP function to get the data from the database, but its got me completely stuck.

Any help greatly appreciated.

Thanks
Phil