How to prevent Autocomplete Caching? I have made textfield to be autocomplete field by using hook_form_alter.

mymoudle_form_alter(&amp;$form, &amp;$form_state, $form_id){
   $form['field_state']['und'][0]['value']['#autocomplete_path'] ='get-state-values';
}
    function mymoudle_drupal_menu() {
    $items = array();   

    $items['get-country-value'] = array(
            'title' =&gt; 'Country Value',
            'page callback' =&gt; '_get_country_value',
            //'page arguments'  =&gt; array(1),
            'access arguments' =&gt; array('access content'),
            'type' =&gt; MENU_CALLBACK,
    );
    $items['get-state-values'] = array(
            'page callback' =&gt; '_get_state_values',
            'access arguments' =&gt; array('access content'),
            'type' =&gt; MENU_CALLBACK
    );
    return $items;
}

function _get_state_values($string){
    $country =$_SESSION['country']; 
    if($country == 'India'){                
        $state = array('Tamilnadu' =&gt; 'Tamilnadu','Karanataka' =&gt; 'Karanataka');
    }
    else{
        $state = array('NewYork' =&gt; 'NewYork','Manahattan' =&gt; 'Manahattan');
    }   
    print drupal_json_output($state);exit;  
}
function _get_country_value(){
    $country = $_REQUEST['valueSelected'];  
    $_SESSION['country'] = $country;
    print drupal_json_output($country);exit;
}


If I select country as India and type in the state as 'n' it shows me in auto-complete as two states with n words like tamilnadu and karnataka which is correct(it runs ajax to fetch the values as shown in screenshot-1).


The issue over here is if I again change the country to 'Us' and type same 'n' it shows same set of results and it doesn't run the ajax(as shown in screenshoot-2). Its showing from cache I think for previous results.



NOTE: I want an fix for the ajax caching issue. 

I have attached the screenshot of what's happening .How to avoid this issue?.Any help will be much appreciated.Thanks in advance.
Since, there is no proper way, I opted for hack (or work around) to get this working. As already mentioned by @Clive, removing/disabling caching mechanism would require more work. This solution just skips the caching part.

Step1: Copy the entire misc/autocomplete.js to your module js scripts directory.

Step2: Comment or remove the following line from the copied file

// See if this key has been searched for before.
  //if (this.cache[searchString]) {
      // We dont want some things to be cached
    //return this.owner.found(this.cache[searchString]);
  //}


Step3: Implement hook_js_alter to override it to specific pages you like.

/**
 * Implements hook_js_alter
 * @param array $javascript
 */
function MYMODULE_js_alter(&amp;$javascript) {
  if (arg(0) == 'MYPAGE') {
    $javascript['misc/autocomplete.js']['data'] = drupal_get_path('module', 'MYMODULE') . '/js/autocomplete.js';
  } 
}