Ajax 跳过成功：function 调用

Question

I'm doing a login with ajax, html and php. I've already debbuged the php, it's ok and it's returning the json variable I need in the ajax call. I have this ajax function:

  $(document).ready(function(){
       $('#login').submit(function() { 
           var username=$("#username").val();
            var password=$("#password").val();
                $.ajax({

                url: 'login.php',
                data: {
                       username: username, 
                       password: password
                      },
                type: 'post',
                dataType: 'json',

                success:function(response){
                    alert(response);
                    if(response.validacion == "ok"){

                        alert("Bienvenidos"),
                        localStorage.loginstatus = "true",                      
                        window.location.assign("home.php");
                    }
                    if(response.validacion == "error"){
                        window.location.assign("login.html"),
                        alert("Datos de usuario incorrectos, inténtelo nuevamente");
                    }   
                }
            });
        });
    });

This is the login.php code: (I know it's really bad save password in cookies, but this is my solution for now)

<?php
 session_start();
?>
<?php
include 'conexion.php';
if(isset($_POST['username'] && $_POST['password'])){
  $username = $_POST['username'];
  $password = $_POST['password'];
}
  $sql = "SELECT * FROM User WHERE username = '$username' OR Email ='$username'";

  $result = $connection->query($sql);

if ($result->num_rows > 0) {

 $row = $result->fetch_array(MYSQLI_ASSOC);
 $hash = $row['password'];
if (password_verify($password, $hash)) { 
    $_SESSION['loggedin'] = true;
    $_SESSION['username'] = $row['username'];
    $_SESSION['start'] = time();

    setcookie("COOKIE_INDEFINED_SESSION", TRUE, time()+31622400);
    setcookie("COOKIE_DATA_INDEFINED_SESSION[username]", $username, time()+31622400);
    setcookie("COOKIE_DATA_INDEFINED_SESSION[password]", $password, time()+31622400);
    echo "Sesión abierta indefinidamente.<br/>";

      $respuesta["validacion"] = "ok";
      $respuesta["id"] = $row["idUser"];
      $respuesta["username"] = $row["username"];
}else{ 
    $respuesta["validacion"] = "error";
    $respuesta["mensaje"] = "Contraseña incorrecta";

}mysqli_close($connection); 
}else{
$respuesta["validacion"] = "error";
$respuesta["mensaje"] = "Usuario incorrecto";
}mysqli_close($connection); 
// encoding array to json format
echo json_encode($respuesta);
?>

I did and inspect element, the username and password are ok, login.php is called, but when I continue the inspection from the line 20, this works until the line 25 aprox and skips to the line 44, the success:function(function) is skipped and the "response" variable is undefined but the login.php is returnint this variable ok:

What am I doing wrong? (sorry for my english, I'm spanish speaker)

Answer 1

Ok, I've solved the problem so I'm going to post what I've done for those who have the same problem:

the function success:function(response) is taking ALL the "echo" from the login.php, so the first "echo" when the login is ok, is the trouble and response become an undefined var. When I post with the wrong credentials, I only have one echo (the json_encode) and I had not problem with the ajax. So the solution will be this, in the php, after the if(password_verify): if (password_verify($password, $hash)) {

      $_SESSION['loggedin'] = true;
      $_SESSION['username'] = $row['username'];
      $_SESSION['start'] = time();

      setcookie("COOKIE_INDEFINED_SESSION", TRUE, time()+31622400);
      setcookie("COOKIE_DATA_INDEFINED_SESSION[username]", $username, time()+31622400);
      setcookie("COOKIE_DATA_INDEFINED_SESSION[password]", $password, time()+31622400);

      $respuesta["validacion"] = "ok";
      $respuesta["id"] = $row["idUser"];
      $respuesta["username"] = $row["username"];
  }else{ 
    $respuesta["validacion"] = "error";
    $respuesta["mensaje"] = "Contraseña incorrecta";

  }
}else{
  $respuesta["validacion"] = "error";
  $respuesta["mensaje"] = "Usuario incorrecto";
}
 mysqli_close($connection); 

// encoding array to json format
echo json_encode($respuesta);
?> 

Answer 2

In order to get the value from the response, you need to JSON.parse() it first to allow your self to use response.validacion