Tabledit with jquery does not work well

I'm trying to learn how to create editable tables with jquery.tabledit.min.js but I'm really not aware of where my judgments are failing.

My table "testC" is:

id fisrt  last
1  juan   a
2  pedro  b
3  diago  c

and my index that I am trying to make work (to edit later and add information about my project):

$conn = sqlsrv_connect( $server, $connectionInfo ); 
//mi conecion a BD esta esta en sql server sqlsrv

$query = "SELECT * FROM testC ORDER BY id DESC";
$result = sqlsrv_query($conn, $query);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.0/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" />  
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>            
<script src="jquery.tabledit.min.js"></script>
//las librerias , tengo ya en mi carpeta el documento con jquery

    <table id="editable_table" class="table table-bordered table-striped">
     <thead>
      <tr>
       <th>ID</th>
       <th>First Name</th>
       <th>Last Name</th>
      </tr>
     </thead>
     <tbody>
     <?php

     while($row = sqlsrv_fetch_array($result)){
      echo '
      <tr>
       <td>'.$row["id"].'</td>
       <td>'.$row["fisrt"].'</td>
       <td>'.$row["last"].'</td>
      </tr>
      ';
     }?>
     </tbody>
    </table>
//la tabla anote mal first y puse fisrt pero lo e dejado asi por cuestiones de 
//ser una tabla test

<script>  
$(document).ready(function(){  
     $('#editable_table').Tabledit({
      url:'action.php',
      columns:{
       identifier:[0, "id"],
       editable:[[1, 'fisrt'], [2, 'last']]
      },
      restoreButton:false,
      onSuccess:function(data, textStatus, jqXHR)
      {
       if(data.action == 'edit')
       {
        $('#'+data.id).remove();
       }
      }
     });

});  
 </script>

and this is my code action.php:

$conn = sqlsrv_connect( $server, $connectionInfo );

$input = filter_input_array(INPUT_POST);

$query = "SELECT * FROM testC WHERE fisrt=? AND last=?";
$parameters = [$_POST["fisrt"], $_POST["last"]];
$result = sqlsrv_query($conn, $query, $parameters);


if($input["action"] === 'edit')
{
 $query_edit = "UPDATE testC 
                   SET fisrt = '$first_name', 
                       last = '$last_name' 
                   WHERE id = '$input["id"]'";

 sqlsrv_query($conn, $query);

}
if($input["action"] === 'delete')
{
 $query_del = "DELETE FROM testC WHERE id = '".$input["id"]."'";sqlsrv_query($conn, $query);

 sqlsrv_query($conn, $query_del);

}
echo json_encode($input);

?>  

currently shows the information of my database and table but when sending an edit it deletes the fields. what would be the problem?