In this demo page page you can see the Current Location shortcode. It was generated using the Current Location Core Extension that is included in GEO my WP core plugin, which is free and can be downloaded from here.
The Current Location add-on provides shortcode and widget that allow the user/visitor to retrieve his current location. The user can either enter an address manually or use the locator icon to dynamically retrieve his current position using the browser HTML5 geolocation.
The current location on the user is saved via cookies and can be used with different features of GEO my WP and the different add-ons.