I have made a form, which adds some lines inside another file, called data.php. Here is the code:
<?php
if (isset($_POST['post'])){
    // GET EMAIL
    $post_text = $_POST["post_text"];
    if($post_text == '') $error = "Post content is empty";
    $filename = getcwd() . "data.php"; 
    $line_i_am_looking_for = 1; 
    $lines = file( $filename , FILE_IGNORE_NEW_LINES ); 
    $lines[$line_i_am_looking_for] = $post_text; 
    file_put_contents( $filename , implode( "\n", $lines ) );
    ?>
    <html>
    <head>
    </header
    <body>
        <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
            <?php
            if ($error) {
            ?>
                <script type="text/javascript">
                    // close the errordiv in secs
                    window.setTimeout("close();", 4000);
                    function close(){
                        document.getElementById("errordiv").style.display="none";
                    }
                </script>
            <?php   
            }   
            ?>
            <div id="errordiv" style="display:block; color:#FF3535">
                <b><?php if($error) echo $error; ?></b>
            </div>
            Email:
            <input name="post_text" size="30" type="text">
            <input class="button" value="Submit" type="submit" name="post">
        </form> 
    </body>
</html>
When I open index.php, enter some words in the text box and submit the form, I want to write the entered text in the second line of data.php file. But it's not working.
 
    