Apple, for example, isn’t exactly making it easy for the people who are developing web apps. Web apps pinned to the home screen on iOS have serious issues that prevent them from working like native apps; for example, they often lose their state when the user switches to another app, and reload when they’re reopened. In fact, Apple is actively making pinned web apps worse.1 Things like the apple-mobile-web-app-capable meta tag are completely broken in iOS 8.
http://ignorethecode.net/blog/2014/11/04/web_apps/