public function toString($str = '')
{
$str .= "<{$this->name} xmlns='{$this->ns}' ";
foreach ($this->attrs as $key => $value) {
if ($key !== 'xmlns') {
$value = htmlspecialchars($value);
$str .= "{$key}='{$value}' ";
}
}
$str .= ">";
foreach ($this->subs as $sub) {
$str .= $sub->toString();
}
$body = htmlspecialchars($this->data);
$str .= "{$body}</{$this->name}>";
return $str;
}