How to get permalink of the questions and answer?

Question

 

How to add link LINK below question ( In qa-a-item-buttons Class) when click on it a popup open and show permalink of the question as shown in image below

i also use this code 

Edited qa-include/qa-page-question-view.php

In function qa_page_q_answer_view(...

Above:
            if ($answer['editbutton'])

Insert:

            $buttons['link']=array(
                'answerid' => $answerid,
            );

Added to:

qa-theme.php

        function form_buttons(...

Above:
                foreach ($form['buttons'] as $key => $button) {...

Insert:

                if (array_key_exists('link', $form['buttons'])) {
                    $answerid = $form['buttons']['link']['answerid'];
                    $link = '<a href="http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REDIRECT_URL'] . "?show=$answerid#a$answerid " . '" .
                    class="qa-form-light-button qa-form-light-button-edit" title="permalink to this answer">link</a>';
                    $this->output($link);
                }

But it not open in popup/textarea