diff --git a/jsproperty.c b/jsproperty.c
index a66c433..4aa3a49 100644
--- a/jsproperty.c
+++ b/jsproperty.c
@@ -252,6 +252,14 @@ static js_Iterator *itflatten(js_State *J, js_Object *obj)
 	return iter;
 }
 
+js_Object *jsV_emptyiterator(js_State *J)
+{
+	js_Object *io = jsV_newobject(J, JS_CITERATOR, NULL);
+	io->u.iter.target = NULL;
+	io->u.iter.head = NULL;
+	return io;
+}
+
 js_Object *jsV_newiterator(js_State *J, js_Object *obj, int own)
 {
 	char buf[32];
diff --git a/jsrun.c b/jsrun.c
index a53d289..68c963e 100644
--- a/jsrun.c
+++ b/jsrun.c
@@ -1469,11 +1469,12 @@ static void jsR_run(js_State *J, js_Function *F)
 			break;
 
 		case OP_ITERATOR:
-			if (!js_isundefined(J, -1) && !js_isnull(J, -1)) {
+			if (js_isundefined(J, -1) || js_isnull(J, -1))
+				obj = jsV_emptyiterator(J);
+			else
 				obj = jsV_newiterator(J, js_toobject(J, -1), 0);
-				js_pop(J, 1);
-				js_pushobject(J, obj);
-			}
+			js_pop(J, 1);
+			js_pushobject(J, obj);
 			break;
 
 		case OP_NEXTITER:
diff --git a/jsvalue.h b/jsvalue.h
index 09427da..05750c9 100644
--- a/jsvalue.h
+++ b/jsvalue.h
@@ -173,6 +173,7 @@ js_Property *jsV_setproperty(js_State *J, js_Object *obj, const char *name);
 js_Property *jsV_nextproperty(js_State *J, js_Object *obj, const char *name);
 void jsV_delproperty(js_State *J, js_Object *obj, const char *name);
 
+js_Object *jsV_emptyiterator(js_State *J);
 js_Object *jsV_newiterator(js_State *J, js_Object *obj, int own);
 const char *jsV_nextiterator(js_State *J, js_Object *iter);