如何在不离开网页的情况下验证Dropbox应用并使用API？

I need users to grant my app permission to access their Dropbox, but I would very much like for them to not have to leave my website and then come back. The authentication API that I know of requires that the user be logged into their Dropbox account, and that they authenticate the app on the Dropbox website. I need users to grant my app permission to acce