public function free()
{
unset($this->tags);
unset($this->page);
unset($this->private_content_tags);
$this->open_forms = array();
$this->complete_forms = array();
$this->frameset = false;
$this->loading_frames = array();
$this->frameset_nesting_level = 0;
$this->left_over_labels = array();
}