mysqli_connect.php

<?php
// Create connection
$mysqli = new mysqli('HOST', 'USER', 'PW');
// Check connection
if ($mysqli->connect_errno) {
    printf("Connect failed: %s\n", $mysqli->connect_error);
    exit();
}
// Check DB server
if ($mysqli->ping()) {
    printf ("Our connection is ok!\n");
} else {
    printf ("Error: %s\n", $mysqli->error);
}
// Close connection
$mysqli->close();