In what language to write a program for (mobile devices) for a hosting of entertainment ads?

Question

Mobile development

Faced with the problem of choosing a language for writing an application (including all aspects by type: design, etc.
The essence of the application: Some hosting of ads for entertainment. There is geolocation and other shushara, a mini-profile with a photo and a rating, respectively, search, etc.
And in general, is it right to create an interface design, and then think about writing when ?

Answer 1

For what types of devices (OS)?... What languages ​​do you know?... It's not clear!
So, offhand: C#, C# + Xamarin.

Answer 2

Looks like PhoneGap is a good fit for you.

Answer 3

Thanks for the advice, if I have knowledge in HTML5 and JS, can I make an application in the form of a website?