HTML5: Exception handling with the Geolocation API

In my previous post on the Geolocation API I passed in a PositionErrorCallback to the geolocation.getCurrentPosition() method. When I received this callback I displayed a generic message informing the user something went wrong. In real-world scenarios you probably want the message to be more specific. You might also want to call a specific fallback method depending on what went wrong.

This is where the PositionError argument of the PositionErrorCallback comes in handy. This object has two properties: code and message.

The code property can return three codes:

• 1: PERMISSION_DENIED
• 2: POSITION_UNAVAILABLE
• 3: TIMEOUT

The message property returns a string describing what went wrong. Be careful, this property is primarily intended for debugging!

Example

The codesnippet below only shows the part where I am handling the PositionErrorCallback. You can find the demo and full source here.

function onError(error){

    var content = document.getElementById("content");        

    var message = "";

    switch (error.code) {

        case 0:

            message = "Something went wrong: " + error.message;

            break;

        case 1:

            message = "You denied permission to this page to retrieve a location.";

            break;

        case 2:

            message = "The browser was unable to determine a location: " + error.message;

            break;

        case 3:

            message = "The browser timed out before retrieving the location.";

            break;

    }

    content.innerHTML = message;

}