Using AJAX to set selected language in Wordpress Session

Simple Example

data = {}; data.action = 'change_language'; data.language = 'en';      jQuery.post( ajaxurl, data, function ( response ) {     console.log( response ); // just for debugging     alert( response.some_more_data );    } ); 

ajaxurl is provided by wordpress and points to wp-admin/admin-ajax.php

PHP-Code:

// place this in your functions.php or where you want function ajax_language_changer() {          $lang = $_REQUEST['language'];          // do stuff to change the language          $response = array(         'request' => $_REQUEST, // just for debugging         'what_ever_you_want' => 'mixed_data',         'some_more_data' => 'Im done',         '     );          wp_send_json( $response );      }  add_action( 'wp_ajax_change_language', 'ajax_language_changer' ); add_action( 'wp_ajax_nopriv_change_language', 'ajax_language_changer' ); 

The hook wp_ajax_nopriv_change_language is for visitors (frontend). wp_ajax_change_language is for logged-in users. In this example ajax works for both.