Thu Oct 28 00:01:20 UTC 2010  pix@kepibu.org
  * Protect hasFeature call.
diff -rN -u old-httpauth/form-to-http-auth.js new-httpauth/form-to-http-auth.js
--- old-httpauth/form-to-http-auth.js	2015-04-15 15:00:56.000000000 +0000
+++ new-httpauth/form-to-http-auth.js	2015-04-15 15:00:56.000000000 +0000
@@ -1,7 +1,9 @@
 (function () {
     function form2httpAuth () {
         /* Skip if the browser indicates it does this itself. */
-        if (document.implementation.hasFeature("HTTPFormAuth", "1.0"))
+        if (document.implementation &&
+            document.implementation.hasFeature &&
+            document.implementation.hasFeature("HTTPFormAuth", "1.0"))
             return true;
 
         /* Attempt login with provided credentials. */