Browser geolocation feature: How can I prompt the user to reuse after they opt out?

Like this question , but in my case I am a web developer. How can I get the browser to ask the user again if they want to allow geolocation? I was hoping I could put some text on the page, something like, "These features are only available if the geolocation services are active, but you turned them down on this site. Click here to try again."

I know how to change the browser to accept this, but how can I help visitors to the page from any browser just enable it with the click of a button.