index_GET.php

<!DOCTYPE HTML>
<html>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <style type="text/css">
        .login {
            height:180px;
            width:230px;
            margin:0;
            border:1px #CCC solid;
            padding:10px;
        }

        .login input {
            padding:5px;
            margin:5px
        }
    </style>
    <body>
        <?php
        if ($_SERVER["REQUEST_METHOD"] == "GET") {
            $username = $_GET["username"];
            $password = $_GET["password"];
            if ($username == "admin" && $password == "admin") {
                echo "<h2>Welcome <span style='color:red'>" .$username. "</span> to website</h2>";
            }
            else{
                echo "<h2><span style='color:red'>Login Error</span></h2>";
            }
        }
        ?>
        <form method="get">
            <div class="login">
                <h2>Login</h2>
                <input type="text" name="username" size="30"  placeholder="username" />
                <input type="password" name="password" size="30" placeholder="password" />
                <input type="submit" value="#"/>
            </div>
        </form>
    </body>
</html>