[whatwg] Week Strings
Smylers at stripey.com
Fri Jun 19 02:48:17 PDT 2009
For <input type=week> elements the spec requires:
The value attribute, if specified, must have a value that is a valid
But the spec's HTML source contains this comment immediately afterwards:
<!-- ok to set out-of-range value, we never know when we might have to
represent bogus input -->
Does that comment mean that the above requirement will be changed to
something along the lines of "must have a value that is a syntactically
valid week string but may represent a week that doesn't actually exist"?
That is, the author can seed a browser's week-picker control to a value
which the browser must not submit back to the server?
In general determining that something is a valid week string requires
knowing which day of the week the year in question begins on. For
example "2009-W53" is a valid week string (because 2009 began on a
Thursday) but "2010-W53" isn't (because 2010 will begin on a Friday).
Browsers will need to do this to know whether they can submit a week
The spec doesn't appear to provide an algorithm for determining which
day of the week a year begins on (however I am not a browser developer;
possibly this is sufficiently straightforward that those who are don't
need it spelling out).
Currently Validator.nu accepts this:
<input type=week value=2010-W53>
but not this:
<input type=week value=2010-W54>
If out-of-range week values are to be permitted in <input> elements then
a validator should permit both of them. Conversely if they aren't
permitted then it should accept neither of them (and therefore have to
implement a 'which day is January 1st' algorithm, which I'm guessing it
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