PHP implements basic authentication

<code><span><?php</span><span>if</span> (!<span>isset</span>(<span>$_SERVER</span>[<span>'PHP_AUTH_USER'</span>]))
{
    header(<span>'HTTP/1.1 401 Unauthorized'</span>);
    header(<span>'WWW-Authenticate: basic realm="Input username and password"'</span>);

    <span>exit</span>;
} <span>else</span> {
    <span>echo</span><span>'Your name is '</span> . <span>$_SERVER</span>[<span>'PHP_AUTH_USER'</span>];
    <span>echo</span><span>'<br>'</span>;
    <span>echo</span><span>'Your password is'</span> . <span>$_SERVER</span>[<span>'PHP_AUTH_PW'</span>];
}</code>