W3C home > Mailing lists > Public > www-style@w3.org > November 2012

[selectors4] Adding User Action Pseudo-classes for touch

From: Wes Johnston <wjohnston@mozilla.com>
Date: Sat, 17 Nov 2012 09:14:50 -0800
Message-ID: <50A7C60A.5040708@mozilla.com>
To: www-style@w3.org
It would be nice when interacting with web pages in touch or pen based 
environments if there were easy ways to style objects based on whether 
they are currently being touched or perhaps if they were touched in the 
last touch session on the screen. I'd like to propose two potential 
selectors for these situations:

1.) :touching for when an element is actively being touched on the 
screen. Unlike targets in the touchevents spec, this should actively 
change as the user moves their finger on the screen. As soon as a user 
lifts their finger from the screen these selectors would no longer 
match. One potential use case for this is something like an onscreen 
keyboard where you want the keys to light up as the user drags their 
finger on the keyboard. This could also be helpful as a means of 
providing quick feedback about what is being touched on screen (i.e. tap 
highlights).

2.) :touched to match the elements that are actively being touched, or 
elements that were being touched the last time a finger was on the 
screen. The use case I want to address here are things like drop down 
menus, where you would likely want them to remain visible on screen even 
after the users finger has been lifted, but to disappear if the user 
touches outside the menu. The selector should be removed as soon as 
another touch starts, ends or moves on the document (i.e. if two fingers 
are on the screen and one is lifted,  the selector should match until 
the second finger moves or another finger touches the document).

In both cases, the selectors should stop matching if the system starts 
performing any system actions on the page (such as scrolling).

Apologies if I'm doing something incorrectly here. Its my first email to 
a working group.

Thoughts?
- Wes
Received on Saturday, 17 November 2012 17:15:30 GMT

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