javascript - can not get json from php to html (sometimes works and sometimes not..) -

i need help...

i have 2 files:

• form.html contains html form
• register.php- gets post request form, registers user in database , returns json contains registered users (i want display them in form.html right after successful registration).

my problem:

i catched submit event , made post request register.php. register file works fine , regiters users db. problem json registers users register.php form.html. can see tried alert json alert(json) in callback function check if came ok. when run code surprised see line alert(json) works , somtimes not no rational reason... want clear: line alert("inserting") , actual user registration db works fine. problem in callback function... perhaps problem related end of register file (the creation of json).

thanks advance!

form.html

        $( "#myform" ).submit(function( event ) {                         if(!validateform()) //there error                         {                             event.preventdefault();                         }                         else                         {                             alert("inserting");                              $(function(){                                 $('#myform[name=new_post]').submit(function(){                                   $.post($(this).attr('action'), $(this).serialize(), function(json) {                                     alert(json);                                   }, 'json');                                   return false;                                 });                             });                         }         }); 

form definition: <form class="form-horizontal" id="myform" role="form" method="post" action="register.php">

register.php

<?php     $srevernme = "localhost";     $username = "root";     $password = "";     $dbname = "mydb";     //create connection     $conn = new mysqli($srevernme,$username,$password,$dbname);      //check connection     if($conn->connect_error)         die("connection failed:". $conn->connect_error);      if ($_server['request_method'] == "post")      {                 if (isset($_post["fnameinput"]) && isset($_post["lnameinput"]) && isset($_post["addressinput"]) && isset($_post["cityinput"]) && isset($_post["zipcodeinput"]))         {             //add new users             // prepare , bind             $stmt = $conn->prepare("insert users (first_name, last_name, address, city, zipcode) values (?, ?, ?, ?, ?)");             if ($stmt == false)                 die("connection failed:");             $stmt->bind_param("sssss",$firstname,$lastname,$address,$city,$zipcode);             $firstname = $_post["fnameinput"];             $lastname = $_post["lnameinput"];             $address = $_post["addressinput"];             $city = $_post["cityinput"];             $zipcode = $_post["zipcodeinput"];             $stmt->execute();             $stmt->close();               //get registers users              $stmt2 = $conn->prepare("select last_name,first_name users order last_name");             if ($stmt2 == false)                 die("connection failed:");             $stmt2->execute();                                $result = $stmt2->get_result();              $arrayformat = array();             while($row = $result ->fetch_assoc())             {                  $arr = array('last_name'=>$row['last_name'],'first_name'=>$row['first_name']);                 $tmp_json = json_encode($arr);                 array_push($arrayformat,$tmp_json);               }             echo json_encode($arrayformat, json_force_object);              $stmt2->close();         }     }      $conn->close(); ?> 

for server side, try this:

if($conn->connect_error):     die("connection failed:". $conn->connect_error); endif; if ($_server['request_method'] == "post"):     if (isset($_post["fnameinput"]) && isset($_post["lnameinput"])         && isset($_post["addressinput"]) && isset($_post["cityinput"])         && isset($_post["zipcodeinput"])):         $stmt = $conn->prepare("insert `users`                  (first_name, last_name, address, city, zipcode)                  values (?, ?, ?, ?, ?)");         if ($stmt == false):             die("connection failed:");         endif;                     $stmt->bind_param("sssss",$firstname,$lastname,$address,$city,$zipcode);         $firstname = $_post["fnameinput"];         $lastname = $_post["lnameinput"];         $address = $_post["addressinput"];         $city = $_post["cityinput"];         $zipcode = $_post["zipcodeinput"];         $stmt->execute();         $stmt->close();         $stmt2 = $conn->prepare("select last_name,first_name                                   `users` order last_name");         if ($stmt2 == false):             die("connection failed:");         endif;         $stmt2->execute();                            $result = $stmt2->get_result();   $formatarray= array();   while($row = $result->fetch_assoc()):      array_push($formatarray, $row); //push result $formatarray        endwhile;   echo json_encode($formatarray, json_force_object);   $stmt2->close();  endif;     endif; $conn->close(); 

and client side:

var form = $("#myform"); $('#myform[name=new_post]').submit(function(e){   e.preventdefault();  $.ajax({         type:"post",         url:"register.php",         data:form.serialize(),         datatype:"json",          success: function(json){          if(json){             var len = json.length;//we calculate length of json             var txt = "";//open blank txt variable             if(len > 0){ //if length greater 0                for(var i=0;i<len;i++){ //as long len greater variable                  if(json[i].first_name && json[i].last_name){                  //we start storing json data txt variable                      txt += "<tr><td>"+json[i].last_name+"</td>                                   <td>"+json[i].first_name+"</td>                              </tr>";                    }                 }             if(txt != ""){              //if data there remove hidden attribute             //and append txt contains data table             //the table given id named 'table'.                $("#table").append(txt).removeclass("hidden");             }          }       }     },     error: function(jqxhr, textstatus, errorthrown){         alert('error: ' + textstatus + ': ' + errorthrown);      }         }); }); 

before submitting form may hide table, in css, add .hidden{display:none;}, below form in form.html.

<table id="table" class="hidden">            <tr>         <th>first name</th>         <th>last name</th>     </tr> </table>