Hi, I'm looking for a way to do geofencing. Many blockchain startups doing an ICO will want this as websites are best when catered to the regulatory environment of the jurisdiction. How can I do geofencing to display a given landing page or web page when a person is coming from a certain geography?
You can use the Geolocation API (see below) that's fairly well supported to ask a user for permission to access their location. Other than that, your only method for identifying a visitor's location is the lookup their IP address, which isn't always accurate. Here's a simply primer on these methods, and the MDN docs on the geolocation API:
The geolocation API allows the user to provide their location to web applications if they so desire. For privacy reasons, the user is asked for permission to report location information.