Need some help with geo-location

Have a client that has five locations and wants the closest one to show up and also have how many miles away it is. It is for Urgent Care Centers.I am not a script person at all. So my question is can this be done and the big one how.
Thanks for any help I can get.

the javascript geolocation functionality has to be allowed by the user … so it won’t run seamless.
getting a accurate location may take a minute or more

when allowed by the user you can get latlong and calculate the distance to other coordinates.