voku\helper\AntiXSS::_do PHP Method

    private function _do($str)
    {
        $str = (string) $str;
        $strInt = (int) $str;
        $strFloat = (double) $str;
        /** @noinspection TypeUnsafeComparisonInspection */
        if (!$str || "{$strInt}" == $str || "{$strFloat}" == $str) {
            return $str;
        }
        // removes all non-UTF-8 characters
        // &&
        // remove NULL characters (ignored by some browsers)
        $str = UTF8::clean($str, true, true, false);
        // decode the string
        $str = $this->decode_string($str);
        // and again... removes all non-UTF-8 characters
        $str = UTF8::clean($str, true, true, false);
        // remove all >= 4-Byte chars if needed
        if ($this->_stripe_4byte_chars === true) {
            $str = preg_replace('/[\\x{10000}-\\x{10FFFF}]/u', '', $str);
        }
        // remove strings that are never allowed
        $str = $this->_do_never_allowed($str);
        // make php tags safe for displaying
        $str = $this->make_php_tags_safe($str);
        // corrects words before the browser will do it
        $str = $this->compact_exploded_javascript($str);
        // remove disallowed javascript calls in links, images etc.
        $str = $this->remove_disallowed_javascript($str);
        // remove evil attributes such as style, onclick and xmlns
        $str = $this->remove_evil_attributes($str);
        // sanitize naughty HTML elements
        $str = $this->sanitize_naughty_html($str);
        // sanitize naughty JavaScript elements
        $str = $this->sanitize_naughty_javascript($str);
        // final clean up
        // This adds a bit of extra precaution in case
        // something got through the above filters.
        $str = $this->_do_never_allowed($str);
        $str = $this->_do_never_allowed_afterwards($str);
        return $str;
    }