bug#43227: EWW ignores 'multiple' attribute of 'select'

[Nicolas Graner <nicolas.graner@universite-paris-saclay.fr>]

Lars Ingebrigtsen <larsi@gnus.org> wrote on 2020-09-07 01:05:
> In the context of the new drop-down menu...
>
> Perhaps they could just be rendered as
>
> [ ] Val1
> [ ] Val2
>
> and if you choose one of them, then we go to 
>
> [x] Val1
> [ ] Val2
>
> (and close the menu), and then you have to open it again to click on:
>
> [x] Val1
> [x] Val2

This looks really awkward. Reopening the menu for each item you want to
select or deselect is inefficient and counter-intuitive. Besides, it
leaves open the question of how to render a multiple select in the eww
buffer, showing which options are selected.

> Because I don't know a way to make the menu stay up after clicking on it.

Pop-up menus are probably not the right tool to implement multiple
selects. There is a reason why graphical browsers offer quite different
interfaces to single and multiple selects.

I stand by my suggestion that a multiple select should look similar to a
list of checkboxes. Maybe it could actually be converted to checkboxes
at the DOM level, before rendering, and then let the normal checkbox
code do the job?

Nicolas