XSS-Filterfunktion in PHP

<?php

/**
 * Function to filter potential XSS attacks
 * @param string $data - The input data to be filtered
 * @return string - The filtered data
 */
function xss_filter($data)
{
    // Remove any non-printable characters
    $data = preg_replace('/[\x00-\x1F\x7F]/', '', $data);

    // Remove any characters that are not allowed in HTML
    $data = preg_replace('/[<>\?\'\"\(\)\[\]]/', '', $data);

    // Remove any characters that are used for XSS attacks
    $data = str_replace(['<', '>', '\'', '\"', ')', '('], '', $data);

    // Return the filtered data
    return $data;
}

// Example usage
$input = "<script>alert('XSS Attack');</script>";
$output = xss_filter($input);

echo $output;

?>