Untitled

<!doctype html>
<html>
    <head>
        <meta charset="utf-8">
        <title>Documento sin título</title>
    </head>
    <body>
        <form role="form" action="procesologin.php" method="POST">
        <input class="form-control" placeholder="Usuario" name="usuario" type="text" autofocus>
        <input class="form-control" placeholder="Contraseña" name="contrasena" type="password" value="">
        <input type="submit" name="submit" class="btn btn-lg btn-primary btn-block" value="Ingresar">
    </body>
</html>

<?php
$server = "localhost";
$user = "root";
$pass = "";
$db = "prueba";
$tabla_db1 = "usuario";
$conexion = new mysqli($server,$user,$pass,$db);
?>

<?php
session_start();
include("conexionprueba.php");
$user = $_POST['usuario'];
$password = $_POST['contrasena'];
$resultado = mysqli_query($conexion,"SELECT * FROM usuarios WHERE user = $user AND password = $password");
if ($consulta = mysqli_fetch_array($resultado)){
    echo "sesion exitosa";}
else{
    echo "sesion no exitosa";}
?>