diff --git a/jquery.chained.js b/jquery.chained.js
index 8784122..1b05c3a 100644
--- a/jquery.chained.js
+++ b/jquery.chained.js
@@ -76,7 +76,7 @@
                     var matches = [];
                     var data = String($(this).data("chained"));
                     if (data) {
-                        matches = data.split(" ");
+                        matches = String(data).split(" ");
                     }
                     if ((matches.indexOf(selected) > -1) || (matches.indexOf(selectedFirst) > -1)) {
                         if ($(this).val() === currentlySelectedValue) {