[whatwg] Proposal to extend registerProtocolHandler

Rich Tibbett richt at opera.com
Wed Jul 6 18:38:06 PDT 2011

Olli Pettay wrote:
> On 07/06/2011 07:51 AM, Robert O'Callahan wrote:
>> I don't think browsers need to prompt for registerProtocolHandler.
>> Instead,
>> I would simply allow any site to register as a protocol handler for
>> almost
>> anything, and remember all such registration
> So all the ad sites (which are embedded via iframe or something) would
> just register all the possible protocols so that some user might
> accidentally use their site for protocol handling - especially if the
> site was the first one to register the protocol.

For registration, we could allow _auto-registration_ of protocol 
handlers only if a.) this is the first time the protocol is being 
registered and b.) when the registration request is coming directly from 
the top-most window context only (i.e. from a web page that users are 
actually visiting).

In all other cases (if you're the nth provider to attempt to register an 
already registered protocol handler or you're not requesting from 
window.top) then the UA would ask the user whether they wish to install 
this handler as the default for the given protocol or not (replacing the 
previous default handler).

For usage, the ideal situation would be for the user to click on a link 
and be auto-directed somewhere without having to select from multiple 
providers each time.

When the user wants to override the default protocol handler then the UA 
could allow e.g. ctrl-shift-click to force show the protocol handler 
dialog to the user. There the user would be free to select any handler 
that the UA has come in to contact with during the course of the user's 
previous browsing sessions (i.e. those handlers that the user decided 
not to set as defaults at the time).

Users should be able to easily detach protocol handlers from this list 
with either [delete] or [delete all handlers for this domain] on this 

- Rich

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