Is it possible to disable HTML in a guestbook? I'm using this script but people can put HTML code in, the code I'm using is:-

PHP Code:
<style>
<!--
p{ text-align: center }
-->
</style>

<body>

<?php

if( empty($_POST['name'])==FALSE && empty($_POST['comments'])==FALSE )
{
    $fp = fopen("data.dat", "a+");
    $data = "<p><b>Name:</b> " . $_POST['name'] . "<br>" . "<b>Comments:</b>" . $_POST['comments'] . "</p>";

    fwrite($fp, $data, 1000);
    fclose($fp);
}

$fr = fopen("data.dat","a+");
$newdata = "";
while ( feof($fr) == FALSE )
{
    $newdata .= fread($fr, 1);
}
echo $newdata;
fclose($fr);
?>
<p>----------------------------------------</p>
<center><h2>Comment</h2></center>
<form method="POST" action="guestbook.php">
<p>
  Name<br>
  <input type="text" name="name" size="30"><br>
  Comments<br>
  <textarea rows="10" name="comments" cols="30"></textarea><br>
  <input type="submit" value="Submit" name="submit"><input type="reset" value="Reset" name="reset">
</p>
</form>