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Re: Touch Event Delay

for

From: Bryan Garaventa
Date: Oct 27, 2015 1:24PM


> For example, with focus and blur events, is the situation that there is a 300ms delay before a focus or blur event is triggered? I am particularly interested
> in the delay as it relates to Voiceover on IOS.

> When navigating with VO, you're unaffected by the delay, as VO itself is responsible for managing your inputs and firing events. In fact, when navigating
> with VO, no touch events are actually passed to the underlying webpage/javascript at all (unless you use a passthrough gesture in VO). In short, don't
> worry about it in this case :)

To clarify one point, though the touch events are intercepted, the onFocus and onBlur handlers are triggered immediately as you move your finger around the screen with VO running.

This is why, if you have a Combobox control that uses onBlur to dismiss the Listbox, it will disappear before you have a chance to read what the Listbox contains unless this is programmed not to do so.


-----Original Message-----
From: WebAIM-Forum [mailto: <EMAIL REMOVED> ] On Behalf Of Patrick H. Lauke
Sent: Tuesday, October 27, 2015 12:00 PM
To: <EMAIL REMOVED>
Subject: Re: [WebAIM] Touch Event Delay

On 27/10/2015 16:45, Tim Harshbarger wrote:
> Patrick,
>
> Again, thanks for the link to the test results and tests you put together. As I read through the material, I noticed you mentioned a 300 millisecond delay. I am not quite sure I understand.

Browsers on touchscreen devices typically have a 300ms delay between the moment your finger/stylus leaves the screen, and the mouse compatibility and click events are fired.

Touch events are fired immediately (finger touches the screen - touchstart; finger moves around - touchmove; finger leaves the screen - touchend). Then 300ms delay. Only then are mouseover, mousedown etc and click fired.

This delay is there because browsers need to wait if this was a single tap, or if this was simply the first instance of a double-tap gesture.
If after 300ms there was no further tap, it's assumed that it was meant as an activation, and the mouse and click events are fired.

(there's a slew of information I could go into about this, but see if any of my presentation http://patrickhlauke.github.io/getting-touchy-presentation/ makes sense)

> For example, with focus and blur events, is the situation that there is a 300ms delay before a focus or blur event is triggered? I am particularly interested in the delay as it relates to Voiceover on IOS.

When navigating with VO, you're unaffected by the delay, as VO itself is responsible for managing your inputs and firing events. In fact, when navigating with VO, no touch events are actually passed to the underlying webpage/javascript at all (unless you use a passthrough gesture in VO). In short, don't worry about it in this case :)

P
--
Patrick H. Lauke

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