[jQuery API] JSON SyntaxError: Unexpected token s

今天call同事的api，發現http status都是200正確，但都跑到$.ajax的error handler

17 Nov 2014 17:39:07,698 [DEBUG] [frmDeviceMgmt] jqXHR.responsetext: undefined log4javascript.min.js:155
17 Nov 2014 17:39:07,700 [DEBUG] [frmDeviceMgmt] textStatus: parsererror log4javascript.min.js:155
17 Nov 2014 17:39:07,700 [DEBUG] [frmDeviceMgmt] errorThrown: SyntaxError: Unexpected token s

查了一下原來是回傳的JSON格式是驗證錯誤的關係，踩雷共勉之:D