Caveats: I suck at accessibility, so I am probably wrong on a lot of things.
Chrome 32 on Android removes the 300ms delay on touch events for responsive sites. This disables double-tap zoom, leaving pinch to zoom the only way to zoom content. This is an accessibility concern, as for some users double tap zoom may have been the only way they were able to zoom web pages.
For unimpaired users, a 300ms delay on link clicks/interactions with sites provides no benefit, and creates a sluggish UI. Many website owners, aware of the impacts of slow UIs, and trying to compete with native apps, used tools like FastClick to override this behaviour by removing the delay. Removing the delay at the browser level negates the need for tools like fastclick, makes chrome feel faster (competitive win for chrome I guess), and improves performance overall as fastclick has scroll performance implications.
A portion of users, who find pinch-to-zoom difficult, will now potentially be left out of the web. While businesses might not be bothered in the short term, this is clearly not a long term good for the web/society.
Chrome 30 on android has an option to force allow zooming on all sites as an accessibility option. If this still exists in Chrome 32, I'd argue this may actually be a step forewards for accessibility. Why?:
- Currently, "dumb" website owners use fast click to disable the 300ms delay: which even with "force allow zooming" enabled breaks double tap zoom.
- As the 300ms delay goes away, website owners can remove fast click, as it will be redundant, which, assuming chrome keeps "force allow zooming" will mean that double tap zoom works again.
Now, the above means that impaired users have to enable an accessibility setting to be able to use their browser, which is a bummer, but at least it puts them back in control if we get rid of hacks like fast click.
Hey, so I work at Google and pushed heavily for the 300ms delay to be dropped in this case.
"300ms is barely anything"
I have to call complete bullshit on this, sorry. Compare http://www.youtube.com/watch?v=BHsVVMCr39Y to http://www.youtube.com/watch?v=i74FAsNNEPQ. The 300ms delay is a huge contributor to the perception that the web on mobile is "slow".
"This is an accessibility concern, as for some users double tap zoom may have been the only way they were able to zoom web pages"
We need to get away from this snake oil hand-wavey approach to accessibility. It's not constructive to invent people with particular disabilities who's experience is now broken. Let's look at the evidence:
Zooming is not disabled
I think everyone here knows this, but I want to make it clear. In older versions of Chrome you could get rid of the 300ms delay by disabling zooming using the meta viewport tag. People did this because of the performance benefit. It's also bad, because zooming is a great feature and relevant to most sites.
In Chrome 32, currently in beta, we've removed the double-tap feature on sites with width=device-width in order to remove the 300ms delay. However, you can still pinch-zoom. Does this create an accessibility issue? First…
Is double-tap even useful?
The double-tap gesture zooms the viewport so the text fits the width of the screen. Another double-tap zooms back.
What do you think double-tap does on a mobile-optimised (width=device-width) site? In the vast majority of cases the text is already at viewport width, so it simply zooms in "a bit". Perhaps this "a bit" is exactly what the user wanted and needed, but probably not. A further double tap zooms back out.
Android has native screen zooming
Android has a whole range of accessibility features, one of which is screen zooming. This works not only in the browser, but across the whole operating system. This feature can also be activated with a single finger, using a triple tap.
Double-tap on mobile optimised pages doesn't do anything particularly useful and in my opinion it's worth dropping to save 300ms per interaction. The reason we make beta releases available is to get feedback on these features, but "what if"s don't cut it. If the removal of double-tap has broken a site for you or someone you know, tell us, file a bug or say something at https://code.google.com/p/chromium/issues/detail?id=169642. We want feedback, but with evidence, not hand-waving.
You may be interested in the discussion at https://twitter.com/stevefaulkner/status/399177271421837312, but more is good.
On the performance team at Chrome we say "Use tools, not rules" because we see a lot of performance "rules" that never worked, or improved performance a number of years ago but now hurt it. A better way is to test and see what actually happens. I feel that accessibility is stuck in "rules" land, and when I did some actual user testing with people with a range of disabilities I was astounded by how badly "rules" had served me in this regard. Part of the reason there's a ton of poor accessibility advice is because we don't have the tools to verify/debunk them. We need better tools, I don't know what those tools are, but we need them.