public function addCondInternal($cond, $script, $pos = 100, array $attr = array())
    {
        $cond = $this->escaper->html($cond);
        $attr = $this->attr(null, $attr);
        $tag = "<!--[if $cond]><script $attr>$script</script><![endif]-->";
        $this->addElement($pos, $tag);

        return $this;
    }