HTML Geolocation API

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The HTML Geolocation API is used to locate a user's position.

Locate the User's Position

The HTML Geolocation API used to get the geographical position of a user.

Note: geolocation is most accurate for devices with GPS, like smartphones.

Note: As of Chrome 50, the Geolocation API will only work on secure contexts such as HTTPS. If your site is hosted on an non-secure orgin (such as HTTP) the requests to get the users location will no longer function.

Using HTML Geolocation

The getCurrentPosition() method is used to return the user's position.

The example below returns the latitude and longitude of the user's position:

HTML Geolocation

Click the button to get your coordinates.

Example explained:

• Check if Geolocation is supported
• If suppoted, run the getCurrentPosition() method. If not, display a message to the user
• If the getCurrentPosition() method is successful, it returns a coordinates object to the function specified in the parameter (showPosition)
• The showPosition() function outputs the Latitude and Longitude

The example above is a very basic Geolocation script, with no error handling

Handling Errors and Rejection

The second parameter of the getCurrentPosition() method is used to handle errors. It specifies a function to run if it fails to get to get the user's location:

HTML Geolocation

Click the buuton to get your coordinates.

Location-specific Information

This page has demonstrated how to show a user's position on a map.

Geolocation is also very useful for location-specific information, like:

• Up-to-data local information
• Showing Points-of-interest near the user
• Turn-by-turn navigation (GPS)

The getCurrentPosition() Method - Return Data

The getCurrentPosition() method returns an object onsuccess. The latitude, longitude and accuracy properties are always returned. The other properties are returned if available:

Geolocation Object - Other interesting Methods

The Geolocation object also has other interesting methods:

• watchPosition() - Returns the current position of the user and continues to return updated position as the user moves (like the GPS in a car).
• clearWatch() - Stops the watchPosition() method

The example below shows the watchPosition() method. You need an accurate GPS device to test this (like smartphone):

HTML Geolocation

Click the button to get your coordinates.