login.php

<?php
/*
        -- To Do --
        * Change values in the connection
        * Change field & table names in the query
*/
session_start();
$db = new mysqli("localhost", "d290986_chav", "courtney1232008", "d290986_mywebsite");
if( isset($_POST) ) {
    /*
        -- To Do --
        * Encrypt password
    */
    $exist = $db->query("SELECT `userid`,`username` FROM `login` WHERE `username`='{$_POST['username']}' AND `password`='{$_POST['pass']}'");
    if( $exist->num_rows ) {
        $r = $exist->fetch_array(MYSQLI_ASSOC);
        $_SESSION['loggedin'] = 1;
        $_SESSION['user'] = $r['user'];
        echo 'You\'ve loggedin!' $r['username'] . PHP_EOL;
    } else {
        echo 'Can\'t find you!' . PHP_EOL;
    }
}
?>
<form action="" method="post">
 Username <input type="text" name="username" length="5" size="5" maxlength="20" /> <br />
 Password <input type="password" name="pass" length="5" size="5" maxlength="25" /> <br />
 <input type="submit" value="login" />
</form>