Any Ruby on Rails library to detect whether drag-n-drop is supported by client device?

I am developing a Ruby-on-Rails-3 website with a few drag-n-drop screens.

Drag-n-drop does not work on all browsers (especially some phones).

Is there an easy way 开发者_运维知识库to know whether the web browser supports drag-n-drop, and use an alternative if not? (could be server-side or client-side)

I could use WURFL and check whether pointing_method=touchscreen, but there must be a more Ruby-on-Rails way to do this?

---

Based on the lack of answers, I guess that the answer is no.