diff --git a/includes/common.inc b/includes/common.inc
index e99b2319c99efd2e001a2d6e35c5c8c8cc98b2fa..398773eb9ace7b4b5672667365c69d4afeb8e9cb 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -4332,8 +4332,8 @@ function drupal_json_decode($var) {
  *   (optional) If set, the variable will be converted to JSON and output.
  */
 function drupal_json_output($var = NULL) {
-  // We are returning JavaScript, so tell the browser.
-  drupal_add_http_header('Content-Type', 'text/javascript; charset=utf-8');
+  // We are returning JSON, so tell the browser.
+  drupal_add_http_header('Content-Type', 'application/json');
 
   if (isset($var)) {
     echo drupal_json_encode($var);