<?php
    session_start();
    $username = trim($_POST['username']);
    $password = trim($_POST['password']);
    /* Create a new mysqli object with database connection parameters */
    $mysqli = mysqli_connect('localhost', 'root', '', 'draftdb');

    if(mysqli_connect_errno())
    {
          echo "Connection Failed: " . mysqli_connect_errno();
          exit();
    }
       /* Create a prepared statement */
    if($stmt = $mysqli -> prepare("SELECT Login_ID, Login_PW,
    FROM login
    WHERE Login_ID=? AND Login_PW =?"))
     {

          /* Bind parameters
             s - string, b - boolean, i - int, etc */
          $stmt -> bind_param("ss", $username, $password);

          /* Execute it */
          $stmt -> execute();

          /* Bind results */
          $stmt -> bind_result($username, $password);

          /* Fetch the value */

          if($stmt->fetch() == true)

             {
             $row =$query -> fetch();
             $_SESSION['name'] = $row;
             header("Location:/in.php");
            exit();
             }
        else
             {
            echo 'Invalid Login';
             }

          /* Close statement */
          $stmt -> close();
       }

       /* Close connection */
       $mysqli -> close();
    ?>

$a = array();
while ($stmt->fetch()) {
    $a = array('username' => $username, 'password' => $password);
}

$_POST['username'];
$_POST['password'];
$username;
$password;

if($stmt->fetch() == true) { } // equals: if ($stmt->fetch()) { }

$sql = "SELECT Login_ID, Login_PW,
  FROM login
  WHERE Login_ID=?
";

$stmt = $mysqli->prepare( $sql );

// Do your thing...

// Make sure the user is found.
if ( ! $stmt->rowCount() )
    return false;

// Retrieve your results as an associative array.
$user = $stmt->fetch();

// Check the password.
if ( ! $_POST['password'] == $user['Login_PW'] ) )
  return false;

$_SESSION['name'] = $user['Login_ID'];

header("Location:/in.php");

exit();