Ticket #12135: general-template.php.diff

wp-includes/general-template.php

@@ -1884 +1884 @@
                 $attributes[] = "dir=\"$dir\"";
 
         if ( $lang = get_bloginfo('language') ) {
-                if ( get_option('html_type') == 'text/html' || $doctype == 'html' )
-                        $attributes[] = "lang=\"$lang\"";
-
-                if ( get_option('html_type') != 'text/html' || $doctype == 'xhtml' )
+                // if doctype is passed as xhtml, use only xml:lang, that is supported by all XHTML versions
+                if ( $doctype == 'xhtml' )
                         $attributes[] = "xml:lang=\"$lang\"";
+                // if MIME is not text/html, use xml:lang too
+                elseif ( get_option('html_type') != 'text/html' )
+                        $attributes[] = "xml:lang=\"$lang\"";
+                // if doctype is not passed as xhtml and MIME is text/html, then use lang
+                else
+                        $attributes[] = "lang=\"$lang\"";
         }
 
         $output = implode(' ', $attributes);