Accessible UIs with jQuery and Infusion
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Accessible UIs with jQuery and Infusion



Overview of accessible Web development techniques with jQuery and Fluid's Infusion application framework. This talk gives developers a primer in DHTML accessibility techniques such as keyboard ...

Overview of accessible Web development techniques with jQuery and Fluid's Infusion application framework. This talk gives developers a primer in DHTML accessibility techniques such as keyboard navigation and ARIA, while teaching them the strengths of Infusion for building large applications in JavaScript.

Presented at 2009 Ajax Experience, Boston.



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    Accessible UIs with jQuery and Infusion Accessible UIs with jQuery and Infusion Presentation Transcript

    • Building Accessible User Interfaces with jQuery and Fluid Infusion Colin Clark, Fluid Project Technical Lead, Adaptive Technology Resource Centre
    • 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
    • Fluid... • Is an open source community of • Designers • Developers • Accessibility experts • Helps other open communities • Consists of universities, museums and individuals
    • What We Do • Offer design advice and resources • Contribute to other communities: • jQuery UI • Dojo • W3C Accessibility • Build Infusion, our JavaScript application framework
    • Introducing
    • 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
    • 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
    • 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
    • Flexible User Interfaces Infusion is an application framework designed to provide unprecedented flexibility while preserving interoperability.
    • Types of JavaScript Tools • Foundational Toolkits • Application Frameworks ... compare and contrast
    • Foundational toolkits • Totally presentation focused • DOM manipulation • Event binding jQuery • Ajax Prototype Dojo core
    • 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
    • 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
    • Deeply Accessible
    • What is Accessibility?
    • 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
    • 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
    • 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
    • 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
    • The Solution • Describe user interfaces with ARIA • Add consistent keyboard controls • Provide flexible styling and presentation
    • Supporting Assistive Technology
    • Opaque Markup // These are tabs. How would you know? <ol> <li><a href=”#cats”>Cats</a></li> <li><a href=”#dogs”>Dogs</a></li> <li><a href=”#gators”>Gators</a></li> </ol> <div> <div id=”cats”>Cats meow.</div> <div id=”dogs”>Dogs bark.</div> <div id=”gators”>Gators bite.</div> </div>
    • Opaque Markup: Tabs
    • ARIA • Accessible Rich Internet Applications • W3C specification in the works • Fills the semantic gaps in HTML • Roles, states, and properties • Live regions
    • 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
    • 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>
    • 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); });
    • Keyboard Accessibility
    • Keyboard Navigation • Everything that works with the mouse should work with the keyboard • ... but not always in the same way • Support familiar conventions
    • 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.
    • Keyboard a11y: Tabs
    • 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>
    • Making Things Tabbable • Tabindex varies subtly across browsers • jquery.attr() normalizes it as of 1.3 • For all the gory details: 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");
    • 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); } });
    • 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()? });
    • Documentation • Tutorial: +Tutorial • API Reference: +Plugin+API
    • 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
    • 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
    • UI Options & FSS
    • UI Options & FSS
    • 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
    • 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
    • Open Architecture
    • 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
    • Handling Markup: Dojo <div class="dijitDialog" tabindex="-1" waiRole="dialog" waiState="labelledby- ${id}_title"> <div dojoAttachPoint="titleBar" class="dijitDialogTitleBar"> <span dojoAttachPoint="titleNode" class="dijitDialogTitle" id="$ {id}_title"></span> <span dojoAttachPoint="closeButtonNode" class="dijitDialogCloseIcon" dojoAttachEvent="onclick: onCancel, onmouseenter: _onCloseEnter, onmouseleave: _onCloseLeave" title="${buttonCancel}"> <span dojoAttachPoint="closeText" class="closeText" title="$ {buttonCancel}">x</span> </span> </div> <div dojoAttachPoint="containerNode" class="dijitDialogPaneContent"></div> </div>
    • Handling Markup: jQuery UI
    • Handling Markup: Infusion fluid.defaults("fluid.fileQueueView", { selectors: { fileRows: ".flc-uploader-file", fileName: ".flc-uploader-file-name", fileSize: ".flc-uploader-file-size", fileIconBtn: ".flc-uploader-file-action", errorText: ".flc-uploader-file-error" },
    • 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
    • Component Families: Reorderer lists images layouts Infusion components come in families
    • More Components Uploader Inline Edit Pager
    • 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
    • Traditional MVC Model n atio oti c State Query State Change ge N n Cha View Selection View Controller User Gestures
    • 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
    • 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
    • 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
    • Playing Nice With Others
    • 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
    • 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
    • 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
    • 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
    • Where We’re Going
    • 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
    • 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
    • Our Mobile Approach • No hard intrusions on your content • Don’t subvert good Web idioms • Your choice: native-like or webbish
    • Infusion Mobile • mFSS: themes for iPhone, Android, more • ScreenNavigator: unobtrusive mobile navigation • Components designed for the mobile Web
    • 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
    • Wrapping Up • Tools for everyone: • ARIA • Dojo • jQuery • Infusion • Give Infusion a try and let us know • We’re a friendly community!
    • Wrapping Up Please fill out an evaluation.
    • Questions?