editing

<div id="maintitle">    Edit a File</div><div id="postbody"><form action="?act=editfilephp1" method="post">    <br><br><center>Which file would you like to edit? (example: posts.txt) (example: stylesheet.css)&nbsp;&nbsp;<textarea rows=1 cols=100 name="filename">enter your file name and extension</textarea></center><br><br><br><br><br><br><br></div><div id="postfooter"><input type="submit" id="submit" value="Edit File" /></form></div>        </body>    </html>    <?php} elseif ( $_GET['act'] == editfilephp1 ) {    $file= "{$_POST['filename']}";if ( $file == "posts.txt" || "posts") {        $file="posts.txt";        $handle=fopen('posts.txt', 'w');        ?>    <br><br><center>Editing posts.txt<br>    <textarea rows=50 cols=100><?php echo file_get_contents('posts.txt'); ?> </textarea></center><?    } elseif ($file == "stylesheet.css" ) {        $file="stylesheet.css";        $handle=fopen('stylesheet.css', 'w');        ?>    <br><br><center>Editing stylesheet.css<br>    <textarea rows=50 cols=100><?php echo file_get_contents('stylesheet.css'); ?> </textarea></center><?    } elseif ($file == "index.php" || "index" || "index file" || "index.html") {        $file="index.php";        $handle=fopen('index.php', 'w');        ?>            <br><br><center>Editing index.php<br>    <textarea rows=50 cols=100><?php echo file_get_contents('index.php'); ?> </textarea></center><?    } else {    ?>    Permission to edit <b>has been denied</b>    <?}}    ?>