Geolocation

Summary

The Geolocation object is used by scripts to programmatically determine the location information associated with the hosting device. The location information is acquired by applying a user-agent specific algorithm, creating a Position object, and populating that object with appropriate data accordingly.

Properties

No properties.

Methods

clearWatch

Stops a specific watch process.

getCurrentPosition

Obtains the current location of the device.

watchPosition

Returns a long value that uniquely identifies a watch operation and then asynchronously starts the watch operation.

Events

No events.

Examples

The geolocation API is published through a geolocation child object within the navigator object. If the object exists, geolocation services are available.

if ("geolocation" in navigator) {
  /* geolocation is available */
  alert("Geolocation services are supported by your browser.");
} else {
 /* geolocation is not available */
  alert("I'm sorry, but geolocation services are not supported by your browser.");
}

The script checks if geolocation is supported, if possible - the script obtains your actual position using the watchPosition method. If something went wrong you will get a detailed error message.

// variables
var watchID;
var geoLoc;

// check if geolocation is available
if ("geolocation" in navigator)
{
/* geolocation is available */
    alert("Geolocation services are supported by your browser.");
    getLocationUpdate();
}

else
{
/* geolocation is not available */
    alert("I'm sorry, but geolocation services are not supported by your browser.");
}

function showLocation(position)
{
alert('latitude: '+position.coords.latitude+' AND longitude: '+position.coords.longitude);
alert(position.coords.accuracy);
}

function errorHandler(err)
{
if(err.code == 0)
{alert("Error: Unknown error");}

else if( err.code == 1)
{alert("Error: Permission denied");}

else if( err.code == 2)
{alert("Error: Position not available");}

else if( err.code == 3)
{alert("Error: Timeout");}

}
function getLocationUpdate(){

   if(navigator.geolocation){
      // timeout at 120000 milliseconds (120 seconds)
      var options = {timeout:120000};
      geoLoc = navigator.geolocation;
      watchID = geoLoc.watchPosition(showLocation,
                                     errorHandler,
                                     options);
   }else{
      alert("Sorry, browser does not support geolocation!");
   }
}

Notes

Windows Internet Explorer 9. The Geolocation object is only supported for webpages displayed in IE9 Standards mode. For more information, see Defining Document Compatibility. The Geolocation object is not supported for applications hosting the WebBrowser Control.

Related specifications

W3C Geolocation Specification

W3C Editor’s Draft

Attributions

• Microsoft Developer Network: Windows Internet Explorer API reference Article