ajax issue with Codeigniter

[eluser]deeptik[/eluser]
I am using BLOB data from table to display content , which contain images url and texts,

If there is any images missing in the content or url is wrong.

Codeigniter session stores absurd value by its own.

How to solve this issue. Plese help me

Code:

function startTest($testid=0){

    $this->session->set_userdata('testid',$testid);
    $this->load->model('testpaper');
$this->session->set_userdata('qCounter',1);
$this->session->set_userdata('lasttime',time()); $data['testparam']= $this->testpaper->testDetail($testid); //get the first question also testid is test paper id

    $questionlist=$this->testpaper->questionlistByTestId($testid);

    $this->session->set_userdata('questionlist',$questionlist);

    $this->session->set_userdata('testid',$testid);

     $this->load->view('view_testheader');
        $this->load->view('view_studentexam',$data);


}

i am storing the questionlist in session

and call the below function on button click

Code:

function nextQuestion($questionId,$response,$end=0){

      $this->load->model('testpaper');

      $s=$this->session->userdata('qCounter');
        $reply[$question]=$response;          

           $res=explode(',',$response);
           foreach($res as $r){
              $permissions[$questionId][]= $r;
            }

         // time code ends


        $per = $this->session->userdata('permission');
        if(is_array($per)){
              $result= $per + $permissions;
              $this->session->set_userdata('permission',$result);

           }
           else{
              $this->session->set_userdata('permission',$permissions);
           }

          $this->session->set_userdata('qCounter',++$s);

          $this->testpaper->nextQuestion($arr[$s]);

  }

below is the model i am calling

Code:

function nextQuestion($questionId){

    $this->load->model('question');
    $question=$this->question->editQuestion($questionId);


                     echo  '<div class="questionblck">';


                           echo $question['childQuestion'][0]['name'];


                      echo '</div>

                       <div class="answerblck">
                                 &lt;textarea name="response" rows="5" cols="70"&gt;&lt;/textarea>
                        </div>';



    echo '&lt;input name="probid" id="probid" type="hidden" value="'.$question['childQuestion'][0]['id'].'"&gt;';




            echo '         </div>

               <div class="float-left gutter-right">';  

                echo    '<div class="float-left">
                             <span class="label">&nbsp;</span>
                             <button type="button" id="prevQuestion">Previous</button>
                        </div>';