<?php
    if (!isset($_REQUEST['username']))
    {
        include 'form.html.php';
    }
    else
    {
        $username = $_REQUEST['username'];
        $password = $_REQUEST['password'];
        $link = mysqli_connect('localhost', 'root', 'youaintgettinmypasswordson');
        if (!$link)
        {
            $output = "Unable to connect to the database server.";
            include "output.html.php";
            exit();
        }
        if (!mysqli_set_charset($link, 'utf8'))
        {
            $output = "Unable to set database connection encoding.";
            include "output.html.php";
            exit();
        }
        if (!mysqli_select_db($link, 'users'))
        {
            $output = "Unable to locate the users.";
            include "output.html.php";
            exit();
        }
        $sql = 'SELECT * FROM users_table WHERE username LIKE "' . $username . '" AND password LIKE MD5("' . $password . '");';
        if (!($result=mysqli_query($link, $sql)))
        {
            $output = "Error querying user database: " . mysqli_error($link);
            include "output.html.php";
            exit();
        }
        if (($row = mysqli_fetch_array($result))==NULL)
        {
            echo "User does not exist, or password incorrect!<br>";
            include 'form.html.php';
        }
        else
        {
            echo "Welcome " . $row['username'] . "!!";
        }

    }
?>