Deux liste deroulante la 2eme s'affiche suivant la 1er

 $connect = odbc_connect("xx", "", "");
					    $query= "select * from Direction ";
                        $result=odbc_exec($connect,$query); 

               
			   
			   
			           echo"<select size='1' id='Direction' name='Direction'>";
					  
						 while($data = odbc_fetch_array($result) )
					 { 
						/*echo 'la direction est '.$data['libdir'].'';*/
					   echo "<option value=".$data["CodeDir"].">".$data["LibDir"]."</option>";
                       
					 }
					   			
					   echo "</select>";
					  
					 echo "<br>";
					 echo"<br>";
					   
					
					    $query1= "select * from Service ";
                        $result1=odbc_exec($connect,$query1);
					  
					   					
					   echo"<select size='1' style='width: 165px; font-size:12px;'  name='Service' id='Service'>";
					 
						
						 while($data1 = odbc_fetch_array($result1) )
					 { 
						/*echo 'la direction est '.$data['libdir'].'';*/
					   echo "<option value=".$data1["CodeSer"].">".$data1['LibSer']."</option>";
                       
					 }
					   			
					   echo "</select>";
						 ?>