wordpress 自动在正文内容后添加内容

function insertFootNote($content) {
if(!is_feed() && !is_home()) {
$content.= "<div class='subscribe'>";
$content.= "<h4>Enjoyed this article?</h4>";
$content.= "<p>Subscribe to our <a href='http://feed.imbolo.com/'>RSS feed</a> and never miss a recipe!</p>";
$content.= "</div>";
}
return $content;
}
add_filter ('the_content', 'insertFootNote');