When you talk about 'mobile app', are you referring to an alternative mobile site the user sees in the browser or packaging it up in something like PhoneGap (or putting it in a native WebView)?
In this case: mobile website. This 'app' runs in the browser and all strategies used here don't rely on anything like PhoneGap. If you need access to certain PhoneGap features you can of course package the app up but it's not required at all.