Javascript will not access json object

Question

When I run the following javascript/php, I keep getting "undefined" when alerting the 'userid' property of the json object. However, if I stringify the json object, it returns "[{'userid':'1'}] which is the correct value.

Why am I getting undefined if I am trying to access the correct name of the json object?

Here is the ajax I am using to access the object:

$.ajax({
  type: 'POST',
  url: 'WebPHP/check_login.php',
  contentType: "application/json; charset=utf-8",
  data: finalObject,
  async: false,
  dataType: 'json',
  success: function(data) {
    if (data["result"] === false) {
      alert("Invalid Email or Password");


    } else {
      var userID = data["result"];
      alert(userID["userid"]);
      var url = "AMessage.html";
      alert(JSON.stringify(data["result"]));

    }
  }
});

And the php that connects to the db:

$json = file_get_contents('php://input');

$jsondata = json_decode($json);

$email = $jsondata - > email;
$password = $jsondata - > password;

$sql1 = " SELECT user_id as userid
FROM users
WHERE email = '$email'
AND password = '$password';
";

$result = mysqli_query($Thesisdb, $sql1) or die(mysqli_error($Thesisdb));

$rows = $result - > num_rows;


while ($row = $result - > fetch_assoc()) {
  $response[] = $row;
}

$post_data = array();

if ($rows == 1) {
  $post_data = array('result' => $response);
} else {
  $post_data = array('result' => false);
}

echo json_encode($post_data);

mysqli_close($Thesisdb);

Does JSON need to have javascript processing triggered to change the view like HTML? It left me scratching my head for a while when I just started playing with ajax, so that could be your problem. Take a look at this project: github.com/ajax-proofs/proofs — a coder
– a coder, Commented Apr 21, 2016 at 1:42
You should be doing something like this while "($rows = $result->num_rows)" to process less also. — a coder
– a coder, Commented Apr 21, 2016 at 1:47

Jack · Accepted Answer · 2016-04-21 01:42:41Z

1

You can't access the userid property because your userID variable contains an array - that's what the [] brackets mean in the json response: [{'userid':'1'}]. Try accessing it this way: alert(userID[0]["userid"]);.

Better yet, don't return an array, since you're checkng that $rows == 1 anyway.

answered Apr 21, 2016 at 1:42

Jack

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Comments

Veshraj Joshi · Accepted Answer · 2016-04-21 03:12:37Z

0

Yes, as said by #Jack you can not access userid property, your json response:[{'userid':'1'}] is in array form, so you need to go for the syntax: alert(userId[0].userid)

answered Apr 21, 2016 at 3:12

Veshraj Joshi

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