Second taxonomy autocomplet depend on first taxonomy autocomplet - drupal-7

Question

Drupal-7
Second taxonomy autocomplet depend on first taxonomy autocomplet.
Add offer:
step 1) Country with autocomplet , City is empty
Country: U
------------USA
City:
step 2) when we select USA then we can use City with autocomplet
Country: USA
City: Be
-------Berkeley
Step 3) but we just insert new item Bexxx
Country: USA
City: Bexxx
Search offer:
Step 1) Country - select USA from the list, City is empty
Country: USA
-----------Germany
City:
Step 2) when we select USA then we have 3 items on the list
Country: USA
City: Berkeley
-------Berlin
-------Bexxxxx

Answer 1

I use Drupal 6, module Hierarchical select and Views. Then in Views I used field with exposed filter.

Answer 2

This is a simple example of dependent fields. Make a simple module named "myajx" and placed this code as it is. Now access through url ie "http://localhost/mypage". Now select a value from first field and you will see only its dependent values are listed in below field.
<?php
/**
* Implementation of hook_menu().
* Registers a form-based page that you can access at "http://localhost/mypage"
*/
function myajx_menu(){
return array(
'mypage' => array(
'title' => 'A page to test ajax',
'page callback' => 'drupal_get_form',
'page arguments' => array('myajx_page'),
'access arguments' => array('access content'),
)
);
}
/**
* A form with a dropdown whose options are dependent on a
* choice made in a previous dropdown.
*
* On changing the first dropdown, the options in the second are updated.
*/
function myajx_page($form, &$form_state) {
// Get the list of options to populate the first dropdown.
$options_first = myajx_first_dropdown_options();
$value_dropdown_first = isset($form_state['values']['dropdown_first']) ? $form_state['values']['dropdown_first'] : key($options_first);
$form['dropdown_first'] = array(
'#type' => 'select',
'#title' => 'First Dropdown',
'#options' => $options_first,
'#default_value' => $value_dropdown_first,
// Bind an ajax callback to the change event (which is the default for the
// select form type) of the first dropdown. It will replace the second
// dropdown when rebuilt
'#ajax' => array(
// When 'event' occurs, Drupal will perform an ajax request in the
// background. Usually the default value is sufficient (eg. change for
// select elements), but valid values include any jQuery event,
// most notably 'mousedown', 'blur', and 'submit'.
'event' => 'change',
'callback' => 'myajx_ajax_callback',
'wrapper' => 'dropdown_second_replace',
),
);
$form['dropdown_second'] = array(
'#type' => 'select',
'#title' => 'Second Dropdown',
'#prefix' => '<div id="dropdown_second_replace">',
'#suffix' => '</div>',
'#options' => myajx_second_dropdown_options($value_dropdown_first),
'#default_value' => isset($form_state['values']['dropdown_second']) ? $form_state['values']['dropdown_second'] : '',
);
return $form;
}
/**
* Selects just the second dropdown to be returned for re-rendering
*
* Since the controlling logic for populating the form is in the form builder
* function, all we do here is select the element and return it to be updated.
*
* #return renderable array (the second dropdown)
*/
function myajx_ajax_callback($form, $form_state) {
return $form['dropdown_second'];
}
/**
* Helper function to populate the first dropdown. This would normally be
* pulling data from the database.
*
* #return array of options
*/
function myajx_first_dropdown_options() {
return array(
'colors' => 'Names of colors',
'cities' => 'Names of cities',
'animals' => 'Names of animals',
);
}
function myajx_second_dropdown_options($key = '') {
$options = array(
'colors' => array(
'red' => 'Red',
'green' => 'Green',
'blue' => 'Blue'
),
'cities' => array(
'paris' => 'Paris, France',
'tokyo' => 'Tokyo, Japan',
'newyork' => 'New York, US'
),
'animals' => array(
'dog' => 'Dog',
'cat' => 'Cat',
'bird' => 'Bird'
),
);
if (isset($options[$key])) {
return $options[$key];
}
else {
return array();
}
}