PHP服务器无法使用ajax接收javascript对象

Question

Hello i am trying to send fields from a from that i saved in a javascript object to a php server. I am using ajax but when i try to receive the object in php i get a length of 0 when debugging. Basically i can't receive the data. Please what did i do wrong.

Javascript code:
    //fields from from saved in an object.
    var obj={
      'user_name': username,
      'pwd': psswd1,
      'user_email': email,
      'user_phone': mobile,
      'sec_quest1': question1,
      'ans1': answer1,
      'sec_quest2': question2,
      'ans2': answer2,
      'user_address': address,
      'user_userInfo': user_info
  };

   console.log(obj);

   var data = JSON.stringify(obj)
   var xhttp = new XMLHttpRequest();

  xhttp.onreadystatechange = function() {
if (xhttp.readyState == 4 && xhttp.status == 200) {
//document.getElementById("txtHint").innerHTML = xhttp.responseText;
    alert(xhttp.responseText);
   }
 } 
 xhttp.open("POST", "server.php", true);
 xhttp.setRequestHeader("Content-type", "application/json");
 xhttp.send(data);
}

php code:

<?php
  $obj = json_decode($_POST["data"]);
 echo 'Name: '.sizeof($obj);
?>

It displays a size of zero meaning it's not receiving the data. Please what did i do wrong

Answer 1

You cant access the post variable when posting JSON to the server so you need to do this.

$str = file_get_contents('php://input'); //($_POST doesn't work here)
$response = json_decode($str, true);

Then retrieve the fields

$name = $response['user_name'];
$phone = $response['user_phone'];
// etc
// or just $response[0], $response[1], $response[2] etc etc

Basically the same answer as techblu3 above, but a little more detailed.