firefox 3 (released yesterday) has many interesting new features, among them web-based protocol handlers. these allow for web-based services what previously was only possible for locally installed programs: to have a service handle a certain URI scheme (
protocol in firefox parlance). people use that all the time for
mailto: URIs, which often are configured to launch the local mail application. in firefox 3, this now can also be configured for web-based email, so that clicking on such a
mailto: link will take users to their web-based email service.
i am interested in that because SMS URIs could benefit from this functionality quite a bit. on devices which have cell phone functions (such as the iPhone), an
sms: URI could easily trigger the phone to let the user compose a text message to the specified recipient. on a normal computer, however, there is no phone network access, so there is no local application which could handle these URIs.
on the other hand, web-based services for sending SMS messages exist, some of them free, others are subscription-based or part of combined messaging suites (i am still a believer in unified messaging, but this idea seems to be completely dead these days). regardless of that, to implement a method how a user clicks on an
sms: URI and then is taken to such a web-based service requires browser support for associating URI schemes and web-based services.
early versions of the SMS URI draft (up to version 13) even had a section on how such a method should be supported by browsers. in version 14, however, this section was removed because of comments saying that this should not be part of the specification. this is probably correct, and it also probably is not something that should be defined by a single URI scheme.
even though i like the fact that firefox 3 now supports such a behavior, it is unfortunate that this behavior is browser-specific, and i think it is unlikely that it will be uniformly supported across different browsers. however, i would love to be proven wrong...