Why won't this script properly sanitize output?
<p>I am trying to sanitize the output of what should be a simple email script, but it only outputs a blank page. Here is the script:</p>

<pre><code>    &lt;?php
define("EMAIL", "info@silentpost.net");

if(isset($_POST['submit'])) {

  //include validation class
  include('./support/validate.class.php');

  //assign post data to variables
  $_POST['name'] = filter_var($_POST['name'], FILTER_SANITIZE_STRING);
  $_POST['email'] = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);
  $_POST['message'] = filter_var($_POST['message'], FILTER_SANITIZE_STRING);

  $name = trim($_POST['name']);
  $email = trim($_POST['email']);
  $message = trim($_POST['message']);

  //start validating our form
  $v = new validate();
  $v-&gt;validateStr($name, "name", 3, 75);
  $v-&gt;validateEmail($email, "email");
  $v-&gt;validateStr($message, "message", 5, 1000);

  if(!$v-&gt;hasErrors()) {
        $header = "From: $email\n" . "Reply-To: $email\n";
        $subject = "email from silentpost.net website!";
        $email_to = EMAIL;

        $emailMessage = "Name: " . $name . "\n";
        $emailMessage .= "Email: " . $email . "\n\n";
        $emailMessage .= $message;

        @mail($email_to, $subject ,$emailMessage ,$header );

    } else {
    //set the number of errors message
    $message_text = $v-&gt;errorNumMessage();

    //store the errors list in a variable
    $errors = $v-&gt;displayErrors();

    //get the individual error messages
    $nameErr = $v-&gt;getError("name");
    $emailErr = $v-&gt;getError("email");
    $messageErr = $v-&gt;getError("message");
  }//end error check


}// end isset
?&gt;
</code></pre>

<p>If I omit the following code, the script will run fine:</p>

<pre><code>$_POST['name'] = filter_var($_POST['name'], FILTER_SANITIZE_STRING);
$_POST['email'] = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);
$_POST['message'] = filter_var($_POST['message'], FILTER_SANITIZE_STRING);
</code></pre>

<p>if necessary, I will include the class, but I don't think it is an issue with the class, as removing the filter_var lines outputs correctly.</p>

<p>Any help would be appreciated.</p>
