diff --git a/src/js/array.js b/src/js/array.js
index e5e8561e48..896b20fc8f 100644
--- a/src/js/array.js
+++ b/src/js/array.js
@@ -853,16 +853,8 @@ DEFINE_METHOD_LEN(
       }
     }
     // Lookup through the array.
-    if (!IS_UNDEFINED(element)) {
-      for (var i = max; i >= min; i--) {
-        if (i in array && array[i] === element) return i;
-      }
-      return -1;
-    }
     for (var i = max; i >= min; i--) {
-      if (i in array && IS_UNDEFINED(array[i])) {
-        return i;
-      }
+      if (i in array && array[i] === element) return i;
     }
     return -1;
   },