<?php
function get_current_page()
{
$page_url = (@$_SERVER["HTTPS"] == "on") ? "https://" : "http://";
$page_url .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
return $page_url;
}
?>

<div class="fb-comments" data-href="<?php echo get_current_page(); ?>" data-num-posts="2" data-width="470"></div>