diff --git a/core/misc/autocomplete.js b/core/misc/autocomplete.js
index 8b0dd72..73b1953 100644
--- a/core/misc/autocomplete.js
+++ b/core/misc/autocomplete.js
@@ -102,7 +102,7 @@ Drupal.jsAC.prototype.onkeyup = function (input, e) {
       return true;
 
     default: // All other keys.
-      if (input.value.length > 0) {
+      if (input.value.length > 0 && !jQuery(input).attr("readonly")) {
         this.populatePopup();
       }
       else {