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    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.


    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.


    If your web application is located at, you can register a protocol handler for it to handle "burger" links like this:

                                      "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 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.

    Note: "Register a webmail service as mailto handler" shows how to do this from XPCOM scope.


    Specified by the WHATWG's Web Applications 1.0 working draft (HTML5).

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Basic support


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

    3.0 (1.9) ? Opera 11.60 ?
    Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Basic support ? 3.0 (3.5) ? ? ?

    See also

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