diff --git a/include/class.format.php b/include/class.format.php
index 6c0ee841b705ba688abc439ab12d5280ae237c8c..b8cfe03be6f60302ce9f5fabd972b012c1694248 100644
--- a/include/class.format.php
+++ b/include/class.format.php
@@ -288,7 +288,7 @@ class Format {
             'schemes' => 'href: aim, feed, file, ftp, gopher, http, https, irc, mailto, news, nntp, sftp, ssh, telnet; *:file, http, https; src: cid, http, https, data',
             'hook_tag' => function($e, $a=0) { return Format::__html_cleanup($e, $a); },
             'elements' => '*+iframe',
-            'spec' => 'iframe=-*,height,width,type,src(match="`^(https?:)?//(www\.)?(youtube|dailymotion|vimeo)\.com/`i"),frameborder'.($spec ? '; '.$spec : ''),
+            'spec' => 'iframe=-*,height,width,type,style,src(match="`^(https?:)?//(www\.)?(youtube|dailymotion|vimeo)\.com/`i"),frameborder'.($spec ? '; '.$spec : ''),
         );
 
         return Format::html($html, $config);