Many sites now use browser geolocation to identify where you are. Your browser uses geolocation features available in your OS to provide location to some sites on request. This feature requires your permission to be active.
Changing your IP with Spotflux will not prevent your location from being shared from your browser if you allow it.
Please see this article for information on blocking this feature: http://www.makeuseof.com/tag/disable-fake-location-firefox-internet-explorer-chrome/