diff --git a/toolkit/components/reader/Readerable.js b/toolkit/components/reader/Readerable.js
index 49e139823..36bfa46d8 100644
--- a/toolkit/components/reader/Readerable.js
+++ b/toolkit/components/reader/Readerable.js
@@ -60,7 +60,7 @@ var Readerable = {
     if (!(uri.schemeIs("http") || uri.schemeIs("https"))) {
       return false;
     }
-    if (!(this.isEnabledForParseOnLoad())) {
+    if (!(this.isEnabledForParseOnLoad)) {
       // TenFourFox issue 585
       // Do this check here as well.
       return false;