+ $description = htmlspecialchars($description, ENT_COMPAT, 'UTF-8', true); // allow double encoding here
+ $title = htmlspecialchars($title, ENT_COMPAT, 'UTF-8', true); // allow double encoding here
+ $author_name = htmlspecialchars($author_name, ENT_COMPAT, 'UTF-8', true); // allow double encoding here
+
+ //<meta name="keywords" content="">
+ $a->page['htmlhead'] .= '<meta name="author" content="'.$author_name.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="title" content="'.$title.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="fulltitle" content="'.$title.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="description" content="'.$description.'" />'."\n";
+
+ // Schema.org microdata
+ $a->page['htmlhead'] .= '<meta itemprop="name" content="'.$title.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta itemprop="description" content="'.$description.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta itemprop="image" content="'.$image.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta itemprop="author" content="'.$author_name.'" />'."\n";
+
+ // Twitter cards
+ $a->page['htmlhead'] .= '<meta name="twitter:card" content="summary" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="twitter:title" content="'.$title.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="twitter:description" content="'.$description.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="twitter:image" content="'.System::baseUrl().'/'.$image.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="twitter:url" content="'.$s[0]["plink"].'" />'."\n";
+
+ // Dublin Core
+ $a->page['htmlhead'] .= '<meta name="DC.title" content="'.$title.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="DC.description" content="'.$description.'" />'."\n";
+
+ // Open Graph
+ $a->page['htmlhead'] .= '<meta property="og:type" content="website" />'."\n";
+ $a->page['htmlhead'] .= '<meta property="og:title" content="'.$title.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta property="og:image" content="'.System::baseUrl().'/'.$image.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta property="og:url" content="'.$s[0]["plink"].'" />'."\n";
+ $a->page['htmlhead'] .= '<meta property="og:description" content="'.$description.'" />'."\n";
+ $a->page['htmlhead'] .= '<meta name="og:article:author" content="'.$author_name.'" />'."\n";
+ // article:tag
+