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Colin Clark Accessible U Is With J Query And Infusion[1]
1. Building Accessible User Interfaces
with jQuery and Fluid Infusion
Colin Clark, Fluid Project Technical Lead,
Adaptive Technology Resource Centre
Monday, September 14, 2009
2. Topics We’ll Cover
• The Fluid community
• Introducing Infusion
• Developing accessible JavaScript
• Infusion’s Architecture
• Techniques for portals, mashups, CMS’s
• Where we’re headed
Monday, September 14, 2009
3. Fluid...
http://fluidproject.org
• Is an open source community of
• Designers
• Developers
• Accessibility experts
• Helps other open communities
• Consists of universities, museums and
individuals
Monday, September 14, 2009
4. What We Do
• Offer design advice and resources
• Contribute to other communities:
• jQuery UI
• Dojo
• W3C Accessibility
• Build Infusion, our JavaScript
application framework
Monday, September 14, 2009
5. Introducing
http://fluidproject.org/products/infusion/
Monday, September 14, 2009
6. World, Meet Infusion
• Application framework built on top of jQuery
• The culmination of our work helping others
• Designed for usability and accessibility
• Open architecture: everything is configurable
Monday, September 14, 2009
7. What’s in Infusion?
• A development framework for building apps
• UI components you can reuse and adapt
• Lightweight CSS framework for styling
• Accessibility tools and plugins for jQuery
Monday, September 14, 2009
8. Building Great UIs Is Hard
• Your code gets unruly as it grows
• UIs are hard to reuse or repurpose
• Design change requires big code change
• Accessibility is confusing
• Combining different code/libraries doesn’t
always work
Monday, September 14, 2009
9. Flexible User Interfaces
Infusion is an application framework designed to
provide unprecedented flexibility while
preserving interoperability.
Monday, September 14, 2009
10. Types of JavaScript Tools
• Foundational Toolkits
• Application Frameworks
... compare and contrast
Monday, September 14, 2009
12. Application frameworks
• Model notifications “something changed here”
• Views to help keep your presentational code clean
• Data binding to sync the display with your model
SproutCore
Dojo/Dijit/
Dojox
Cappuccino
Monday, September 14, 2009
13. Infusion is Different
• Accessibility baked right in
• Carefully designed interactions
• Markup is in your control
• Not the same old MVC
• Supports portals, mashups and CMS’s
Monday, September 14, 2009
16. A New Definition
• Accessibility is the ability of the system to
accommodate the needs of the user
• Disability is the mismatch between the user
and the interface provided
• We all experience disability
• Accessible software = better software
Monday, September 14, 2009
17. Assistive Technologies
• Present and control the user interface in
different ways
• Not just screen readers!
• Use built-in operating system APIs to
understand the user interface
Screen readers
Screen magnifiers
On-screen keyboards
Monday, September 14, 2009
18. DHTML: A New Can of Worms
• Shift from documents to applications
• Familiar a11y techniques aren’t enough
• Most DHTML is completely inaccessible
• New techniques are still being figured out
Monday, September 14, 2009
19. The Problem
• Custom widgets often look, but don’t act,
like their counterparts on the desktop
• HTML provides only simple semantics
• Not enough information for ATs
• Dynamic updates require new design
strategies to be accessible
Monday, September 14, 2009
20. The Solution
• Describe user interfaces with ARIA
• Add consistent keyboard controls
• Provide flexible styling and presentation
Monday, September 14, 2009
24. ARIA
• Accessible Rich Internet Applications
• W3C specification in the works
• Fills the semantic gaps in HTML
• Roles, states, and properties
• Live regions
Monday, September 14, 2009
25. Roles, States, Properties
• Roles describe widgets not present in HTML 4
• slider, menubar, tab, dialog
• Properties describe characteristics:
• draggable, hasPopup, required
• States describe what’s happening:
• busy, disabled, selected, hidden
Monday, September 14, 2009
26. Using ARIA
// Now *these* are Tabs!
<ol id=”animalTabs” role=”tablist” tabindex=”0”>
<!-- Individual Tabs shouldn’t be focusable -->
<!-- We’ll focus them with JavaScript instead -->
<li role=”tab”><a href=”#” tabindex=”-1”>Cats</a></li>
<li role=”tab”><a href=”#” tabindex=”-1”>Dogs</a></li>
<li role=”tab”><a href=”#” tabindex=”-1”>Gators</a></li>
</ol>
<div id=”panels”>
<div role=”tabpanel” aria-labelledby=”cats”>Cats meow.</div>
<div role=”tabpanel” aria-labelledby=”dogs”>Dogs bark.</div>
<div role=”tabpanel” aria-labelledby=”gators”>Gators bite.</div>
</div>
Monday, September 14, 2009
27. Adding ARIA in Code
// Identify the container as a list of tabs.
tabContainer.attr("role", "tablist");
// Give each tab the "tab" role.
tabs.attr("role", "tab");
// Give each panel the appropriate role,
panels.attr("role", "tabpanel");
panels.each(function (idx, panel) {
var tabForPanel = that.tabs.eq(idx);
// Relate the panel to the tab that labels it.
$(panel).attr("aria-labelledby", tabForPanel[0].id);
});
Monday, September 14, 2009
29. Keyboard Navigation
• Everything that works with the mouse
should work with the keyboard
• ... but not always in the same way
• Support familiar conventions
http://dev.aol.com/dhtml_style_guide
Monday, September 14, 2009
30. Keyboard Conventions
• Tab key focuses the control or widget
• Arrow keys select an item
• Enter or Spacebar activate an item
• Tab is handled by the browser. For the rest,
you need to write code. A lot of code.
Monday, September 14, 2009
32. Tabindex examples
<!-- Tab container should be focusable -->
<ol id=”animalTabs” tabindex=”0”>
<!-- Individual Tabs shouldn’t be focusable -->
<!-- We’ll focus them with JavaScript instead -->
<li id=”tab1”>
<a href=”#cats” tabindex=”-1”>Cats</a>
</li>
<li id=”tab2”>
<a href=”#cats” tabindex=”-1”>Dogs</a>
</li>
<li id=”tab3”>
<a href=”#cats” tabindex=”-1”>Alligators</a>
</li>
</ol>
Monday, September 14, 2009
33. Making Things Tabbable
• Tabindex varies subtly across browsers
• jquery.attr() normalizes it as of 1.3
• For all the gory details:
http://fluidproject.org/blog/2008/01/09/
getting-setting-and-removing-tabindex-values-with-javascript/
// Make the tablist accessible with the Tab key.
tabContainer.attr("tabindex", "0");
// And take the anchors out of the Tab order.
$(“a”, tabs).attr("tabindex", "-1");
Monday, September 14, 2009
34. Adding the Arrow Keys
// Make each tab accessible with the left and right arrow keys.
tabContainer.fluid("selectable", {
selectableSelector: that.options.selectors.tabs,
direction: fluid.a11y.orientation.HORIZONTAL,
onSelect: function (tab) {
$(tab).addClass(that.options.styles.highlighted);
},
onUnselect: function (tab) {
$(tab).removeClass(that.options.styles.highlighted);
}
});
Monday, September 14, 2009
35. Making Them Activatable
// Make each tab activatable with Spacebar and Enter.
tabs.fluid("activatable", function (evt) {
// Your handler code here. Maybe the same as .click()?
});
Monday, September 14, 2009
36. Documentation
• Tutorial:
http://wiki.fluidproject.org/display/fluid/Keyboard+Accessibility+Tutorial
• API Reference:
http://wiki.fluidproject.org/display/fluid/Keyboard+Accessibility+Plugin+API
Monday, September 14, 2009
37. Infusion Goes Deeper
• jQuery Keyboard Navigation Plugin
• ARIA everywhere
• Everything is highly adaptable and flexible
• UI Options and the Fluid Skinning System:
• Users can customize their environment
Monday, September 14, 2009
38. UI Options
• One size doesn’t fit all
• Allows users to customize your app:
• layout
• styling
• navigation
• Uses FSS by default; can be configured to
work with your own classes
Monday, September 14, 2009
41. CSS Frameworks
“If you’re going to use a framework, it
should be yours; one that you’ve created.
You can look at existing frameworks for
ideas and hack at it. But the professionals
in this room are not well served by picking
up a framework and using it as-is.”
- Eric Meyer
Monday, September 14, 2009
42. Fluid Skinning System
• FSS is built to be hacked on
• Provides a core set of building blocks
• Reset, text, layouts, themes
• Namespaced: no conflicts with your stuff
• Themes for better legibility & readability
http://wiki.fluidproject.org/x/96M7
Monday, September 14, 2009
44. Markup Agnosticism
• HTML is so fundamental to Web UIs
• Others lock away markup in a black box
• Markup should be totally free to edit, adapt,
or replace
• Libraries shouldn’t bake in assumptions
about your markup
• Unobtrusiveness everywhere
Monday, September 14, 2009
48. Components
“Components suck. Apps built with components look like it”
• Infusion components aren’t black boxes
• Fundamentally adaptable:
• Change the markup
• Restyle with CSS
• Add/replace actual behaviour
• Everything is super-loosely coupled
Monday, September 14, 2009
50. More Components
Uploader Inline Edit
Pager
Monday, September 14, 2009
51. Model, View... but not Controller
• MVC is a given in most framework
• JavaScript’s functional idioms offer
alternatives (hint: events)
• Infusion has no controller layer at all
• ... and none of the classical inheritance cruft
that usually goes with it
Monday, September 14, 2009
52. Traditional MVC
Model
n
atio
oti c
State Query State Change
ge N
n
Cha
View Selection
View Controller
User Gestures
Monday, September 14, 2009
53. The Problem with Controllers
• Controllers are the least defined
• What’s “glue?”
• Always referred to as the non-reusable part
• MVC has been warped over the decades
• The framework should take care of the glue
Monday, September 14, 2009
54. Infusion Models & Views
Model
• Controller is replaced by events Change Noti cation
• Reads to the model are transparent
• State changes and notification are
just events State Query State Change
• Transparent architecture: you can use View
the same events we use
Framework
Monday, September 14, 2009
55. Plain Old Models
• M is the most important thing in your app
• Data needs to travel seamlessly between
client and server
• Most toolkits force a model to extend
some base class or particular structure
In Infusion, models are just plain old JSON
Monday, September 14, 2009
57. Portals, Mashups, and CMS’s
• These days, diverse code and markup coexists
• Most JavaScript is written as if it owns the
whole browser
• As you combine stuff, things can break
• Namespacing and privacy is essential
Monday, September 14, 2009
58. Writing Collision-Free JavaScript
• Put code in a unique namespace
• Use closures for privacy
• Support more than one on the page
• Scope all variables to an instance
• Avoid hard-baking ID selectors
• Constrain selectors within a specific element
Monday, September 14, 2009
59. Keeping it to Ourselves
• Infusion takes namespacing seriously
• We won’t steal your names
• Components are carefully scoped
• We won’t accidently grab the wrong stuff
• Infusion doesn’t expect control of the page
Monday, September 14, 2009
60. Tying it All Together
• Infusion helps you with accessibility
• Components you can really work with
• Simple structure so your code can grow
• Totally transparent, event-driven design
• Markup and models are under your control
• No inheritance or controller cruft
Monday, September 14, 2009
62. Infusion Next Steps
• Infusion 1.2 coming in October:
• New lightweight Inversion of Control
• Data Grid and reworked Pager components
• Lots of bug fixes
• New demos portal with example code
• Screencasts
Monday, September 14, 2009
63. Fluid Engage
• Open source collaboration with museums
• Visitor engagement: learn and contribute
• Use phones visitors bring into the museum
• Mobile apps and in-gallery kiosks
• All built with open source Web technology
Monday, September 14, 2009
64. Our Mobile Approach
• No hard intrusions on your content
• Don’t subvert good Web idioms
• Your choice: native-like or webbish
Monday, September 14, 2009
65. Infusion Mobile
• mFSS: themes for iPhone, Android, more
• ScreenNavigator: unobtrusive mobile navigation
• Components designed for the mobile Web
Monday, September 14, 2009
66. Kettle: Server-side JS
• Built on top of the JSGI server spec
• Don’t need lots of new APIs on server
• Envjs provides a full browser
• Infusion as application framework
• Choose where markup gets rendered
• Natural, familiardesigners for Web
developers and
environment
Monday, September 14, 2009
67. Wrapping Up
• Tools for everyone:
• ARIA
• Dojo
• jQuery
• Infusion
• Give Infusion a try and let us know
• We’re a friendly community!
Monday, September 14, 2009
68. Wrapping Up
Please fill out an evaluation.
Monday, September 14, 2009
69. Questions?
http://fluidproject.org
Monday, September 14, 2009
