Is basically "html_special_chars", but supports a couple of flags:
<?php
$flags = array(
'FILTER_FLAG_STRIP_LOW', 'FILTER_FLAG_STRIP_HIGH',
'FILTER_FLAG_ENCODE_HIGH',
);
$filter = FILTER_SANITIZE_SPECIAL_CHARS;
include 'presentations/slides/input-filter/render-form.php';
include 'presentations/slides/input-filter/check-data.php';
?>
Output