csfr codeigniter code example

Example: csrf in codeigniter 3

<!doctype html>
<html>
<head>
   <title>How to Send AJAX request with CSRF token in CodeIgniter</title>
</head>
<body>

    <!-- CSRF token (Here, name is 'csrf_hash_name' which is specified in $config['csrf_token_name'] in cofig.php file ) --> 
    <input type="text" class="txt_csrfname" name="<?= $this->security->get_csrf_token_name(); ?>" value="<?= $this->security->get_csrf_hash(); ?>"><br>   

    Select Username : <select id='sel_user'>
      <option value='yssyogesh'>yssyogesh</option>
      <option value='sonarika'>sonarika</option>
      <option value='vishal'>vishal</option>
      <option value='sunil'>sunil</option>
    </select>

    <!-- User details -->
    <div >
       Username : <span id='suname'></span><br/>
       Name : <span id='sname'></span><br/>
       Email : <span id='semail'></span><br/>
    </div>

    <!-- Script -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
    <script type='text/javascript'>
    // baseURL variable
    var baseURL= "<?= base_url();?>";

    $(document).ready(function(){

       $('#sel_user').change(function(){
          // CSRF Hash
          var csrfName = $('.txt_csrfname').attr('name'); // Value specified in $config['csrf_token_name']
          var csrfHash = $('.txt_csrfname').val(); // CSRF hash
          
          // Username
          var username = $(this).val();

          // AJAX request
          $.ajax({
            url:'<?=base_url()?>index.php/User/userDetails',
            method: 'post',
            data: {username: username,[csrfName]: csrfHash },
            dataType: 'json',
            success: function(response){

              // Update CSRF hash
              $('.txt_csrfname').val(response.token);

              // Empty the elements
              $('#suname,#sname,#semail').text('');
 
              // Loop on response
              $(response[0]).each(function(key,value){

                 var uname = value.username;
                 var name = value.name;
                 var email = value.email;

                 $('#suname').text(uname);
                 $('#sname').text(name);
                 $('#semail').text(email);
              });

            }
         });
       });
    });
    </script>
</body>
</html>