I am currently working on a Firefox add-on that utilizes GPS to determine the user's location and triggers a specific action when they are in close proximity to a certain point. For example, the add-on should only take action when green users are near.
I have access to the latitude and longitude of the user, but I need to figure out how to calculate whether they are within range of another (black) point. All of this needs to be accomplished using JavaScript. Does anyone have any suggestions on how I can achieve this? Or any recommendations on resources I should look into?
Thank you in advance!