diff --git a/util.js b/util.js
index 6cbb9ac..338574f 100644
--- a/util.js
+++ b/util.js
@@ -6,7 +6,7 @@ var templatePage, templateBookDetail, templateMain, currentData, before, filterL
 
 var cache = new LRUCache(30);
 
-var DEBUG = true;
+var DEBUG = false;
 var isPushStateEnabled = window.history && window.history.pushState && window.history.replaceState &&
   // pushState isn't reliable on iOS until 5.
   !navigator.userAgent.match(/((iPod|iPhone|iPad).+\bOS\s+[1-4]|WebApps\/.+CFNetwork)/);