--- a/playground/jsonld.js	Fri Apr 20 17:19:38 2012 -0400
+++ b/playground/jsonld.js	Fri Apr 20 17:29:43 2012 -0400
@@ -387,6 +387,9 @@
   callback = arguments[callbackArg];
 
   // set default options
+  if(!('base' in options)) {
+    options.base = '';
+  }
   if(!('resolver' in options)) {
     options.resolver = jsonld.urlResolver;
   }
@@ -501,6 +504,9 @@
   var callback = arguments[callbackArg];
 
   // set default options
+  if(!('base' in options)) {
+    options.base = '';
+  }
   if(!('resolver' in options)) {
     options.resolver = jsonld.urlResolver;
   }