diff --git a/htdocs/samples/data_label_format.html b/htdocs/samples/data_label_format.html
index 466a4a0..1fe0566 100644
--- a/htdocs/samples/data_label_format.html
+++ b/htdocs/samples/data_label_format.html
@@ -17,8 +17,8 @@
           labels: {
 //            format: function (v, id) { return "Default Format on " + id; },
             format: {
-              y: function (v, id) { return "Y Format on " + id; },
-              y2: function (v, id) { return "Y2 Format on " + id; }
+              data1: function (v, id) { return "data1 Format"; },
+              data2: function (v, id) { return "data2 Format"; }
             }
           },
           axes: {