diff --git a/includes/common.inc b/includes/common.inc
index 80822d4..08feb62 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -2577,8 +2577,8 @@ function drupal_to_js($var) {
  *   (optional) If set, the variable will be converted to JSON and output.
  */
 function drupal_json($var = NULL) {
-  // We are returning JavaScript, so tell the browser.
-  drupal_set_header('Content-Type: text/javascript; charset=utf-8');
+  // We are returning JSON, so tell the browser.
+  drupal_set_header('Content-Type: application/json; charset=utf-8');
 
   if (isset($var)) {
     echo drupal_to_js($var);