[whatwg] Why children of datalist elements are barred from constraint validation?
ian at hixie.ch
Mon May 2 15:36:56 PDT 2011
On Fri, 31 Dec 2010, Mounir Lamouri wrote:
> On 12/31/2010 03:20 AM, Ian Hickson wrote:
> > On Fri, 24 Sep 2010, Mounir Lamouri wrote:
> >> I agree that a child of a datalist element should not block the form
> >> submission. However, I'm wondering why do we care about this
> >> particular edge case when there are a lot of situations where an
> >> element can be invalid without any possible action from the user.
> >> If there is no specific use cases in mind I think we should just
> >> remove that.
> > It's so that you can use a <select> in the <datalist> (with the same
> > <option>s) for fallback in older UAs, without that <select> having any
> > effect on the form submission.
> I do not understand that the <select> inside the <datalist> should not
> be invalid but why it *has* to be barred from constraint validation?
> Adding the required attribute to the select element in that case would
> be stupid and useless. The other way to make the <select> element
> invalid would be by calling .setCustomValidity(). Is there a real use
> case that require calling .setCustomValidity() in batch? Even if, can't
> we rely on the authors not calling .setCustomValidity() on elements that
> should not be invalid? We already do that for non-displayed elements,
> don't we?
> You should take into account that this requirement force the UA to check
> the entire parent tree to prevent a situation that can happen in various
> other ways.
<select> in a <datalist> is completely ignored for form submission. In
fact, any form element at all in <datalist> is ignored for form
submission. See the "construct the form data set" algorithm:
It's so that you can do things like:
<input ... list=options>
...maybe other form controls here...
Basically everything in the <datalist> except the <option> elements is for
fallback in legacy UAs and is ignored in new UAs.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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