From d3ee2211c273810bffddede45393b51af7f1e70b Mon Sep 17 00:00:00 2001
From: Takeharu Oshida <takeharu.oshida@mobilus.co.jp>
Date: Tue, 20 May 2014 20:48:39 +0900
Subject: [PATCH] Avoid Uncaught TypeError

---
 jquery.dynatable.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/jquery.dynatable.js b/jquery.dynatable.js
index d08aba3..785771e 100644
--- a/jquery.dynatable.js
+++ b/jquery.dynatable.js
@@ -960,8 +960,8 @@
         var aAttr = (a['dynatable-sortable-text'] && a['dynatable-sortable-text'][attr]) ? a['dynatable-sortable-text'][attr] : a[attr],
             bAttr = (b['dynatable-sortable-text'] && b['dynatable-sortable-text'][attr]) ? b['dynatable-sortable-text'][attr] : b[attr],
             comparison;
-        aAttr = aAttr.toLowerCase();
-        bAttr = bAttr.toLowerCase();
+        aAttr = aAttr ? aAttr.toLowerCase() : (aAttr+"").toLowerCase();
+        bAttr = bAttr ? bAttr.toLowerCase() : (bAttr+"").toLowerCase();
         comparison = aAttr === bAttr ? 0 : (direction > 0 ? aAttr > bAttr : bAttr > aAttr);
         // force false boolean value to -1, true to 1, and tie to 0
         return comparison === false ? -1 : (comparison - 0);