Ajax code to submit form in Codeigniter

ajax.php

$('#submit').click(function(){
 var formData = new FormData($('#form')[0]);

    $.ajax({

      url: '<?php echo base_url();?>controller/method',
      type: 'POST',
      data: formData,
      async: false,
      success: function(data) {   
      alert('form submitted');
      $('#form')[0].reset();
      },
      error: function(data){

        alert('error');

      },
      cache: false,
      contentType: false,
      processData: false

    }); 
    return false; 

});