Index: includes/ajax.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/ajax.inc,v
retrieving revision 1.37
diff -u -p -r1.37 ajax.inc
--- includes/ajax.inc	21 Oct 2010 19:31:39 -0000	1.37
+++ includes/ajax.inc	20 Nov 2010 02:00:04 -0000
@@ -471,20 +471,19 @@ function ajax_deliver($page_callback_res
   }
 
   // This function needs to do the same thing that drupal_deliver_html_page()
-  // does: add any needed http headers, print rendered output, and perform
-  // end-of-request tasks. By default, $header=TRUE, and we add a
+  // does: add any needed HTTP headers, print rendered output, and perform
+  // end-of-request tasks. By default, $header = TRUE, and we add a
   // 'text/javascript' header. The page callback can override $header by
   // returning an 'ajax' element with a #header property. This can be set to
-  // FALSE to prevent the 'text/javascript' header from being output, necessary
-  // when outputting to an IFRAME. This can also be set to 'multipart', in which
-  // case, we don't output JSON, but JSON content wrapped in a textarea, making
-  // a 'text/javascript' header incorrect.
-  if ($header && $header !== 'multipart') {
+  // 'multipart', in which case, we don't output JSON, but JSON content wrapped
+  // in a textarea, making a 'text/javascript' header incorrect.
+  if ($header) {
     drupal_add_http_header('Content-Type', 'text/javascript; charset=utf-8');
   }
   $output = ajax_render($commands);
   if ($header === 'multipart') {
-    // jQuery file uploads: http://malsup.com/jquery/form/#code-samples
+    // Handle jQuery Form file uploads.
+    // @see http://malsup.com/jquery/form/#file-upload
     $output = '<textarea>' . $output . '</textarea>';
   }
   print $output;