javascript - JQuery is not picking up echo from php -

i'm echoing message ('ok') php script jquery ajax call.

i'm echoing out correct message, , showing in console when log it, appropriate jquery function not firing - according code should password has been changed successfully" message, "there problem" message - can suggest reason why?

here code first php:

if(isset($_post['oldpass'])){     $oldpass = mysql_real_escape_string($_post['oldpass']);     $newpass = mysql_real_escape_string($_post['newpass']);     $sql = "select password, salt users email='$log_email' , id='$log_id' limit 1";     $query = mysqli_query($db_conx, $sql);     $numrows = mysqli_num_rows($query);     if($numrows > 0){         while($row = mysqli_fetch_array($query, mysqli_assoc)){             $current_salt = $row["salt"];             $db_pass = $row["password"];         }          $old_pass_hash = crypt($oldpass, $current_salt);         if ($old_pass_hash != $db_pass){             echo "problem";             exit();         }     }     $s = "$2a$10$";     $random = randstrgen(20);     $salt = $s.$random;     $p_crypt = crypt($newpass, $salt);     $sql = "update users set password='$p_crypt', salt='$salt' email='$log_email' , id='$log_id' limit 1";     $query = mysqli_query($db_conx, $sql);     if ($query == true){         $_session['password'] = $p_crypt;         echo 'ok';         exit();     }  } ?> 

this javascript/jquery

function change_password(){     var oldpass = $('#old_pass').val();     var newpass = $('#new_pass').val();     var newpass_conf = $('#confirm_new_pass').val();      if(newpass != newpass_conf){         $('#status').html("your passwords not match");     } else if(newpass=="" || oldpass==""){         $('#status').html("you have not entered anything");     }     $.ajax({       type: 'post',       url: "changepassword.php",       datatype: 'text',       data: {           "oldpass": oldpass,            "newpass": newpass_conf    },       success:function(data){           if(data == "ok"){               $('#change_password_form').html("<h2> success</h2><div class='noerror'><p> password has been changed successfully.</p> <p> may close window.</p></div>");           } else {               $('#status').html("there problem");           }        }     }); }  $(document).ready(function(){     $(document).on('click','#change_password', function(){     change_password(); });   }); </script> 

and html

<div> <h1>change password</h1></div><hr>   <form id="change_password_form" class="input" onsubmit="return false;">   <div> <label for="old_pass">current password:</label>     <input id="old_pass" type="text" class="searchbox" onfocus="emptyelement('status')" maxlength="88" value=""></div>   <div> <label for="new_pass">new password:</label>     <input id="new_pass" class="searchbox" type="text"  onfocus="emptyelement('status')" maxlength="88" value=""> </div>  <div><label for="confirm_new_pass">confirm new password:</label>     <input id="confirm_new_pass" class="searchbox" type="text"  onfocus="emptyelement('status')" maxlength="88" value=""><div>    <input type="button" style="position:relative;top:10px; float:right;" id="change_password" value="change password"></form>     <span id="status" class="statuserror"></span> </body> </html> 

change datatype: "json" in ajax call

then in php code return json data
json_encode(array('response'=>'ok'));

your ajax success function should this,

success: function (data) {     var resultobject = jquery.parsejson(data);         if(rersultobject['response']=='ok') {             $('#change_password_form').html("<h2> success</h2><div class='noerror'><p> password has been changed successfully.</p> <p> may close window.</p></div>");         } else {             $('#status').html("there problem");         }     } }` 

here parsejson used convert json string javascript object.