Navigator.registerProtocolHandler()

Allows web sites to register themselves as possible handlers for particular protocols.

For security reasons, by default, web sites may only register protocol handlers for themselves — the domain and protocol of the handler must match the current site. However, users may set a preference in Firefox to allow cross website installation, by setting the gecko.handlerService.allowRegisterFromDifferentHost pref to true in about:config.

Extensions can register protocol handlers targeting other sites: see the 'See Also' section for how to use them from XPCOM.

Syntax

window.navigator.registerProtocolHandler(protocol, uri, title);

• protocol is the protocol the site wishes to handle, specified as a string.
• uri is the URI to the handler as a string. You can include "%s" to indicate where to insert the escaped URI of the document to be handled.

  Note: MUST be of http or https scheme

• title is the title of the handler presented to the user as a string.

Example

If your web application is located at http://www.google.co.uk, you can register a protocol handler for it to handle "burger" links like this:

navigator.registerProtocolHandler("burger",
                                  "https://www.google.co.uk/?uri=%s",
                                  "Burger handler");

This creates a handler that allows burger:// links to direct the user to your web application, inserting the burger information specified in the link into the URL. Recall that this script must be run from the same domain (so any page location at google.co.uk) and the second argument passed must be of http or https scheme (in this example it is https) .

The user will be notified about registering this protocol, see the below image for an example.

Specifications

Browser compatibility

[1] Protocol whitelist includes mailto, mms, nntp, rtsp, and webcal. Custom protocols must be prefixed with web+.

See also

• Web-based protocol handlers
• RegisterProtocolHandler Enhancing the Federated Web at Mozilla Webdev
• Web Application APIs - Custom scheme and content handlers - Whitelisted schemes
• Register a webmail service as mailto handler shows how to do registerProtocolHandler from XPCOM scope.
• XPCOM Interface Reference > nsIWebContentHandlerRegistrar > registerContentHandler - This shows how to use this function XPCOM scope