fix #1692 @0.25

diff --git a/js/libs/fluidbook/fluidbook.slider.js b/js/libs/fluidbook/fluidbook.slider.js
index 18decfc1a86c091885935f6d244ace0b9bb51716..3cc3597e649b17c162a84a328244a924dc92f73e 100644 (file)
--- a/js/libs/fluidbook/fluidbook.slider.js
+++ b/js/libs/fluidbook/fluidbook.slider.js
@@ -65,7 +65,9 @@ FluidbookSlider.prototype = {
             $("#slider").removeClass("drag");
         }
         if (move) {
-            this.updatePageByCursorPosition(this.pageToSlider(e.center.x), end, true);
+            if (e.center != undefined) {
+                this.updatePageByCursorPosition(this.pageToSlider(e.center.x), end, true);
+            }
         }
     },