There are two ways in which this application or website gets your location (latitude and longitude coordinates) and we attempt to get it in this order:
1- Using the geolocation capabilities of your browser. This method requires your approval or consent (that's why you should get a pop-up asking for it) and it's the most accurate way to know where you are, as it leverages the GPS capabilities of your device (e.g. smartphone and tablet). Even for devices without GPS sensors like most desktop computers, there are now clever ways in which geolocation services get the location; for example, using what it is called Wi-Fi positioning.
2- Using your IP address. If for whatever reasons we cannot get your location using the first method (as described above), then as a fallback option we try to get your location from your IP address. This is a lot less accurate, but it should at least produce the town or city where you are located.