    public function __construct() {
        $this->_tidy = new csstidy();
        $this->_tidy->set_cfg('lowercase_s', false);
        $this->_id_attrdef = new HTMLPurifier_AttrDef_HTML_ID(true);
        $this->_class_attrdef = new HTMLPurifier_AttrDef_CSS_Ident();
        $this->_enum_attrdef = new HTMLPurifier_AttrDef_Enum(array('first-child', 'link', 'visited', 'active', 'hover', 'focus'));
    }
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.