config.php

<?php

  $host = "localhost"; // host name ...
  $user = "root"; // username database
  $pass = ""; // pass database
  $database = "vietbook"; // choose database

  $connection = mysqli_connect($host, $user, $pass, $database) or die('cant connect');  
  mysqli_query($connection, "SET NAMES 'utf8'"); // importance !