Jukka K. Korpela writes: > 2014-02-19 11:10, Smylers wrote: > > > Jukka K. Korpela writes: > > > > > The point is that year numbers aren't really "numbers" in a normal > > > sense, any more than car plate numbers, credit card numbers, > > > product numbers, or social security numbers are. Surely they can > > > be regarded as numbers, but so can car plate numbers and the > > > others. > > > > Except that years do actually form a sequence, and it's possible to > > perform maths on them; for instances, subtracting one year from > > another yields a duration > > Mathematically, you are right, but input types aren't based on general > properties of quantities but on practical classification of input > data.

That's a reasonable way of doing it. > All the examples I gave, including year numbers, are normally input by > typing the digits Many other numbers — actual, no-doubt-about-it, definitely 100% genuine numbers — are also typically typed in. > - in contrast with, say, using a color picker, a data picker, or a > slider. There are situations where up/down arrows makes sense on years. For instance, a chart of various baby names could have a box for the year currently being displayed, and it's handy to be able to nudge that along by a year at a time to see it change, without having to manually retype the year. Or when displaying one year's tax return, with the ability to display other years' returns — with adjacent years being likely options. Obviously not every year actually gets treated as a number, but there are many situations where they are, and where a number input control makes sense for them. Contrast this with credit card numbers or telephone numbers, which never actually get treated as numbers (unless you want a form with the ability to easily cycle through the final digit of a credit card number until it passes the mod 10 check!). > And year numbers differ, as mentioned, from normal numbers as regards > to conventional formats (e.g., 2014 vs. 2,014 or 2'014 or 2 014 > or...). Many people, at least in the UK, don't bother with a thousands separator in 4-digit numbers anyway, but probably would put them in a 5-digit year. The style guides Mike quoted (which in general did use commas in 4-digit numbers) also had other categories apart from years which don't use commas, including page numbers. Page numbers are undoubtedly numbers, and it definitely makes sense to provide up/down arrows for them. So if we wish to be able to follow those style guides, we still need to be able to provide comma-less <input type=number> controls for page numbers, regardless of whether you consider a year to be a number. If we don't care about following those style guides, we could simply go with Hixie's suggestion of never putting thousands separators in 4-digit numbers. In neither case does decreeing that years aren't numbers actually help. Cheers Smylers -- http://twitter.com/Smylers2