diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index b21ea29a592..b37fc71fbee 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -3354,16 +3354,16 @@ class core_renderer_ajax extends core_renderer {
      */
     public function header() {
         // MDL-39810: IE doesn't support JSON MIME type if version < 8 or when it runs in Compatibility View.
-        $supports_json_contenttype = !check_browser_version('MSIE') ||
+        $supportsjsoncontenttype = !check_browser_version('MSIE') ||
                 (check_browser_version('MSIE', 8) &&
                     !(preg_match("/MSIE 7.0/", $_SERVER['HTTP_USER_AGENT']) && preg_match("/Trident\/([0-9\.]+)/", $_SERVER['HTTP_USER_AGENT'])));
         // unfortunately YUI iframe upload does not support application/json
         if (!empty($_FILES)) {
             @header('Content-type: text/plain; charset=utf-8');
-            if (!$supports_json_contenttype) {
+            if (!$supportsjsoncontenttype) {
                 @header('X-Content-Type-Options: nosniff');
             }
-        } else if (!$supports_json_contenttype) {
+        } else if (!$supportsjsoncontenttype) {
             @header('Content-type: text/plain; charset=utf-8');
             @header('X-Content-Type-Options: nosniff');
         } else {