OWA离线功能是Exchange 2013 中的一个新功能
Offline Access is a new feature in Exchange 2013 Outlook Web App (OWA) that allows you to continue working on your emails while disconnected from the Internet.
相关链接说明
http://office.microsoft.com/en-us/support/using-outlook-web-app-offline-HA102828007.aspx
To use offline access, you need at least Internet Explorer (Internet Explorer: A Web browser that interprets HTML files, formats them into Web pages, and displays them to the user. You can download Internet Explorer from the Microsoft Web site at http://www.microsoft.com.) 10, Safari 5, or Chrome 24
默认情况下OWA必须连接到Exchange Server才能访问,而OWA的离线功能,就是在我们和Exchange Server断开连接的情况下也能访问OWA.