There is a new HTML Permissions API that uses Promises to let users set browser permissions in their browser for things like Geolocation and Notifications.

Currently only supported in Chrome and Firefox...

Code GIST: https://gist.github.com/prof3ssorSt3v3/8a0a4963c8b981c364ed3cca771f79de

Google Developer Reference: https://developers.google.com/web/updates/2015/04/permissions-api-for-the-web