How do I get the longitude and latitude of a user?

Question

I am using the Geolocation API in HTML5 to show the user their longitude and latitude. However it constantly tells me that the location is unavailable even though I am allowing the request to show my location. Anyone knows what to do to fix this? My research tells me I need to uses https:// but I am not sure how this applies.

UPDATE:
This is my code:
https://code.sololearn.com/WKqjh3x7B6W9
I am now getting a latitude and longitude but I am not sure if it is working correctly.