Re: Proposal for "Cascading Attribute Sheets" - like CSS, but for attributes!

On Aug 21, 2012 6:18 PM, "Tab Atkins Jr." <jackalmage@gmail.com> wrote:
>
> On Tue, Aug 21, 2012 at 3:15 PM, Brian Kardell <bkardell@gmail.com> wrote:
> > On Aug 21, 2012 5:40 PM, "Tab Atkins Jr." <jackalmage@gmail.com> wrote:
> >> On Tue, Aug 21, 2012 at 2:28 PM, Ojan Vafai <ojan@chromium.org> wrote:
> >>> On a somewhat unrelated note, could we somehow also incorporate jquery
> >>> style
> >>> live event handlers here? See previous www-dom discussion about this:
.
> >>> I
> >>> suppose we'd still just want listen/unlisten(selector, handler)
methods,
> >>> but
> >>> they'd get applied at the same time as cascaded attributes. Although,
we
> >>> might want to apply those on attribute changes as well.
> >>
> >> Using CAS to apply an "onfoo" attribute is nearly the same (use a
> >> string value to pass the function, obviously).  It'll only allow a
> >> single listener to be applied, though.
> >>
> >> If it's considered worthwhile, we can magic up this case a bit.  CAS
> >> properties don't accept functions normally (or rather, as I have it
> >> defined in the OP, it would just accept a FUNCTION token, which is
> >> just the function name and opening paren, but I should tighten up that
> >> definition).  We could have a magic function like listen(<string>)
> >> that, when used on an onfoo attribute (more generally, on a
> >> host-language-defined "event listener" attribute) does an
> >> addEventListener() call rather than a setAttribute() call.
> >
> > Can you give some pseudo code or something that is relatively close to
what
> > you mean here?  I'm not entirely sure I follow.
>
> Sure!
>
> So, in my current proposal, you can just set an onfoo attribute:
>
> ul.special > li {
>   onclick: "alert('You clicked me!');
evt.target.classlist.add('clicked');";
> }
>
> Here's a suggestion for a similar API that would invoke
> addEventListener instead of setAttribute:
>
> ul.special > li {
>   onclick: listen("alert('You clicked me!');
> evt.target.classlist.add('clicked');");
> }
>
> ~TJ

This feels a lot like netscape's old actionsheets proposal.  Doesn't it
create the same footgun I mentioned above though?  Would you be blocked off
from accessing dom in those handlers? Or are the read only (you may
remember you, borris and I discussed how that might work last year)  In
other words, what is preventing you from writing...

.foo .bar{
    onclick: listen(create a .bar and attach it as a child of evt.target);
}