On Mon, Jul 20, 2009 at 2:47 PM, Peter Kasting<[email protected]> wrote: > Two unrelated comments. > First, it seems a bit odd to me that <input type=email> and <input type=url> > are validated (for typeMismatch problems) but <input type=tel> isn't. I > know it's prohibitively difficult to perfectly validate telephone number > formats given the variety around the world, but it's also prohibitively > difficult to validate email addresses per the relevant RFC, which is why > HTML5 specs a much simpler algorithm that at least rejects obviously bad > input. > > It seems like perhaps <input type=tel> could set typeMismatch if the input > contained no numeric digits at all, or maybe if it contained characters > outside 0-9, +, -, (, ), ' ', ...? Maybe the level of "validation" provided > by these proposals is so low that it's not worth doing, though.
You got it. While emails officially have a very complex format, in practice they follow a fairly simple, restricted format that can be usefully validated. Telephone numbers, on the other hand, differ wildly across the globs, and you can't just identify a restricted subset that 'most' fall into. Even if you could identify a sane subset of validation that you could apply widely, it would be weak enough to be worth basically nil in terms of actually ensuring that you've received a valid telephone number. ~TJ
