javascript - Upload File Using Ajax in Codeigniter -

i trying upload file other data. thing i'm getting error you did not select file upload. can't understand i'm doing wrong. glad if can point out doing wrong.

html file

 <div class="modal-body">           <form id="add_message" enctype="multipart/form-data"  method="post" action="<?php echo base_url() ?>apps/messages/composemessage">              <div class="form-group">               <select id="messageto" class="form-control" data-plugin="select2" multiple="multiple" data-placeholder="to:" name="messageto">               </select>             </div>              <div class="form-group">               <input class="form-control" placeholder="subject" id="messagesubject" name="messagesubject"></input>             </div>              <div class="form-group">               <textarea  data-provide="markdown" data-iconlibrary="fa" rows="10" id="messagebody" name="messagebody"></textarea>             </div>              <input type="hidden" name="fname" value="" id="formname" ></input>              <div class="left">                  <!-- <span class="btn green fileinput-button"> -->                      <input id="message_attachement" type="file" name="file_attac" size="20" >                 <!-- </span> -->             </div>             <!-- <button class="btn btn-primary"  type="submit" value="submit">send</button> -->           </form>         </div>         <div class="modal-footer text-left">           <button class="btn btn-primary" data-dismiss="modal"  id="addformbutton">send</button>           <button class="btn btn-primary" data-dismiss="modal"  id="saveformbutton">save</button>           <a class="btn btn-sm btn-white btn-pure" data-dismiss="modal" href="javascript:void(0)">cancel</a>         </div> 

js

$("#addformbutton").on('click' , function(){     debugger;                $.ajax({             type: "post",              url: base_url + "apps/messages/composemessage",             async: false,              mimetype: "multipart/form-data",             datatype:json,              data:{                 'reciever': $('#messageto').val() ,                  'subject': $('#messagesubject').val(),                 'text': $('#messagebody').val(),                 'type': 'active',                 'msgid': $('#formname').val(),                 'attachment' : $('#message_attachement').val()             },             success: function(response){             },             error: function(response){             }         });     }); 

controller

 $this->load->helper('file_upload');          $filename = $this->input->post('attachment');           $path = 'uploads/attachments/';           $allowed_types = 'erb|php|txt';           $redirect = '';           // error_log("outside");           if (!empty($this->input->post('attachment'))) {               // error_log("inside");               // error_log ("parameters: " . $path." types: ". $allowed_types." name: ". $filename." redirect: ". $redirect);               $parameters['profile_pic'] = file_upload($path, $allowed_types, $filename, $redirect);               // error_log("the path ");               // error_log($parameters['profile_pic']);               if ($this->session->set_userdata("img_errors")) {                 // error_log("error");                 return false;               }           } 

file upload function

  function file_upload($upload_path , $allowed_types , $filename , $redirect)   {       $ci = & get_instance();        $config['upload_path'] = $upload_path;       $config['allowed_types'] = $allowed_types;       // $config['max_size'] = 1024;//1mb       // $config['max_width'] = 1024;       // $config['max_height'] = 1024;        $ci->load->library('upload', $config);       $data = null;       if (!$ci->upload->do_upload($filename)) {         error_log("within file"); //          $error = array('error' => $ci->upload->display_errors());         error_log($ci->upload->display_errors());           $ci->session->set_userdata('img_errors', $ci->upload->display_errors());           //error_log(print_r($ci->upload->display_errors(),true));           // redirect(base_url() . $redirect);       } else {         error_log("uploading");           $data = array('upload_data' => $ci->upload->data());           // do_resize($config['upload_path'] , $data['upload_data']['file_name']);       }        return $config['upload_path'] . $data['upload_data']['file_name'];   } 

this working code used in recent project, code self explanatory feel free ask question.

html:

                <form action="http://localhost/index.php/upload_file" method="post" style="display:none;" id="file_upload_form" enctype="multipart/form-data">                     <input type="file" id="dialog_triggerer" name="uploaded_file">                 </form>                  <button class="btn btn-default btn-fab-sm" id="file_attach">                     <span class="mdi-file-attachment"></span>                 </button> 

js:

trigger code on action:

            var form = $('form')[0]; // standard javascript object here             var formdata = new formdata(form);              if($("#dialog_triggerer").val()!=""){                  $.ajax( {                   url: frontend_url + '/upload_file',                   type: 'post',                   data: formdata,                   processdata: false,                   contenttype: false,                   async: false                 } ).done(function(data){                     file_data = json.parse(data);                     new_post.file_data = file_data;                 });               } 

upload_file ctrl:

<?php  class upload_file extends ci_controller{     public function __construct(){         parent::__construct();     }      public function index(){          $valid_file=true;         $message;           //if did upload file...         if($_files['uploaded_file']['name'])         {             //if no errors...             if(!$_files['uploaded_file']['error'])             {                 //now time modify future file name , validate file                 $new_file_name = strtolower($_files['uploaded_file']['name']); //rename file                 if($_files['uploaded_file']['size'] > (20024000)) //can't larger 20 mb                 {                     $valid_file = false;                     $message = 'oops!  file\'s size large.';                 }                  //if file has passed test                 if($valid_file)                 {                     $file_path = 'themes/uploads/'.$new_file_name;                     move_uploaded_file($_files['uploaded_file']['tmp_name'], fcpath . $file_path);                     $message = 'congratulations!  file accepted.';                 }             }             //if there error...             else             {                 //set returned message                 $message = 'ooops!  upload triggered following error:  '.$_files['uploaded_file']['error'];             }         }         $save_path = base_url().$file_path;          $name = $_files['uploaded_file']['name'];         $size = $_files['uploaded_file']['size'];         $type = $_files['uploaded_file']['type'];           $data = array(             "message" => $message,             "save" => $save_path,             "name" => $name,             "size" => $size,             "type" => $type         );          $this->load->view('upload_file/upload_file.php', $data);       } } 

upload_file.php view:

<?php  $res = array(     "msg" => $message,     "path" => $save,     "name" => $name,     "size" => $size,     "type" => $type );  echo json_encode($res);    ?>