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You have completed Accessibility for UX Designers!
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People with disabilities must be able to Operate your web content. The Operable principle is all about removing barriers between your user and your content.
WCAG Operable Principle
- Keyboard navigation
- Obvious focus indicators
- Allow enough time
- Disable distracting content
- Careful with flashing animations
- Help users navigate
- Make the link purpose clear
- Provide alternatives to complex interactions
- Generous target sizes
Further reading
- Keyboard Compatibility
- Keyboard Accessibility
- What are Keyboard Traps?
- Mac Accessibility Shortcuts
- Ways we make the Slack iOS app accessible
- Photosensitivity and Seizures
- I Used The Web For A Day Using A Screen Reader
- Headings | Usability & Web Accessibility
- Touch Gesture Guide
- Appleβs UI Design Dos and Donβts
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People with disabilities must be
able to operate your web content.
0:00
The Operable principle is all about
removing barriers between your user and
0:05
your content.
0:10
Many users rely solely on
a keyboard to navigate the web,
0:15
either due to a temporary or
situational disability or
0:21
a permanent disability related
to vision or motor skills.
0:26
The first Operable criteria
requires testing that all
0:36
interactive elements
are accessible using the tab key.
0:40
Keyboard users need to be able to
exit each interface element as well,
0:46
avoiding what's known as a keyboard trap.
0:51
In this example,
I can use the tab key to select the next
0:55
interface element or
shift-tab to return to the previous one.
0:59
A blue focus indicator shows me
which element is currently selected.
1:06
However, once I enter the form input
labeled Last 4 digits of your Tax ID,
1:12
I'm stuck, unable to move forwards or
backwards.
1:19
That's a keyboard trap and is extremely
frustrating for keyboard-only users.
1:24
Providing keyboard shortcuts is a great
way to help your keyboard-only audience,
1:31
as long as you make the shortcuts easy to
learn and the documentation easy to find.
1:37
I'm reviewing a document called
Mac accessibility shortcuts
1:44
with a list of shortcuts for
activating common accessibility features
1:49
such as the VoiceOver screen reader
as well as instructions on using
1:54
your keyboard like a mouse to navigate and
interact with items on screen.
1:59
Designers should ensure focus indicators,
2:08
which highlight the currently selected
element, are visually obvious.
2:11
The indicators must remain visible and
2:18
obvious no matter what element is
selected, whether main menus or
2:21
sub-navigations, form fields or
drop-down menus.
2:26
Trying to navigate a site that lacks
focus indicators using a keyboard
2:32
is like operating a mouse
with no visible cursor.
2:37
You'd never know what you're clicking.
2:40
It's worth noting that
designing accessible interfaces
2:44
often requires combining
a number of WCAG criteria.
2:48
For example,
here's a screen capture of the macOS
2:53
Accessibility Options menu in
both light and dark modes.
2:56
However, in dark mode, the contrast
ratio between the focus indicator and
3:02
the background doesn't come
close to the minimum standard.
3:07
Keyboard-only users are forced to either
guess which option is selected or
3:12
switch to light mode.
3:17
The second guideline of the operable
principle, Enough Time,
3:22
states that when completing a task such
as booking a flight has a time limit,
3:26
users should be able to adjust or disable
the time limit if they need extra time.
3:32
WCAG makes an exception for
3:39
when the time limit is an essential
part of how the content is experienced.
3:40
For example,
if an eBay auction has lasted a week and
3:45
is set to expire in an hour,
that's essential to how eBay works.
3:49
But if a user wins an auction and
needs extra time to fill out
3:55
a form full of purchasing details,
the WCAG requires eBay
4:00
to make extending or
disabling the time limit easy for users.
4:05
Users should also have the option
to disable distracting content.
4:11
For some Slack users,
4:18
a message like this one with an animated
GIF might make concentration difficult.
4:19
Fortunately, the Slack app allows users
to disable animated GIFs and emojis.
4:25
Under the main Slack menu,
4:32
I'll choose Preferences,
then click the Accessibility menu.
4:34
Slack gives me options to
increase font size and
4:40
to adjust keyboard navigation features.
4:44
And here's the option to block
animated images and emojis.
4:47
Now I can see the image
is no longer moving.
4:53
I've included a link to an article
on Slack's accessibility features in
4:57
the teacher's notes.
5:02
The third operable guideline is called
Seizures and Physical Reactions and states
5:06
that animation should never flash more
than three times in any one-second period.
5:12
To learn more about
providing safe visuals,
5:19
I've included a link in
the teacher's notes to an article by
5:22
the Epilepsy Foundation called
Photosensitivity and Seizures.
5:26
The fourth guideline, Navigable,
states that users should be
5:33
able to navigate, find content,
and determine where they are.
5:38
Designers should understand
the importance of using descriptive,
5:45
easily identifiable headings
to organize content.
5:49
For example, I'm looking at an article
from Smashing Magazine called
5:54
I Used The Web For
A Day Using A Screen Reader.
5:58
As a visual reader, I can scan my
eye over the content headings,
6:02
such as What Is A Screen Reader and
How To Enable And Use Your Screen reader,
6:07
followed by subheadings,
like VoiceOver On Desktop and
6:16
VoiceOver on Mobile.
6:21
This lets me quickly decide whether
the content below the heading is relevant.
6:25
Screen readers function in a similar way.
6:32
Users can navigate using headings and
6:35
skip to a desired heading to
begin reading at that point.
6:38
The Navigable guideline also
specifies that the purpose of a link
6:44
should be clear from the link text alone.
6:49
Here are two different
links to the same content.
6:53
However, in the first example,
the clickable text reads "click here",
6:57
which gives no clue to what the user
will find after clicking the link.
7:03
This is poor SEO practice, as search
engines value descriptive text links.
7:08
But this could also frustrate
users of screen readers
7:15
who are able to tab directly to hyperlinks
without reading the full sentence.
7:18
In the second example,
the sentence has the same meaning, but
7:25
the clickable text reads
"basketball videos".
7:29
Now the user knows what to expect.
7:32
The final Operable guideline
is called Input Modalities and
7:37
covers interaction beyond the keyboard.
7:42
I'm looking at a resource called
the Touch Gesture Reference Guide.
7:46
The movements diagrammed here are familiar
to many users of touch screen devices.
7:51
Because users of assistive technologies
might not be capable of such
7:58
complex interactions,
the Input Modalities guideline
8:03
suggests making alternative
navigation available
8:08
that can be activated by a simple tap,
click, or physical gesture.
8:11
In addition, the Input Modalities
guideline states that interface
8:20
elements should be a minimum
of 44 square pixels in size.
8:25
You'll notice this is a AAA guideline,
but I think it's a pretty critical one.
8:31
As illustrated by Apple's UI Design Dos
and Don'ts, buttons that are too small or
8:37
placed too close together are difficult
to accurately tap with a finger.
8:44
Unfortunately, Apple didn't
follow its own recommendations
8:50
when creating the macOS interface.
8:54
The red, yellow, and
green circles in the upper-left
8:57
corner of each application
window to close, minimize,
9:03
and maximize are only
about 16 pixels in size.
9:08
Tests have shown that users with
disabilities relating to motor skills
9:14
have struggled to click
these buttons with a mouse.
9:19
The WCAG recommendation for
more generous target sizes
9:22
would have made MacOS
windows more accessible.
9:27
So keep those guidelines handy to
ensure the interfaces you design
9:31
can be operated by users
with disabilities.
9:36
Up next,
we'll examine the letter U in POUR,
9:41
making our Web content Understandable.
9:45
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