type: widget

release: 1.5

status: released

documentation: http://api.jqueryui.com/accordion/

demo: http://jqueryui.com/accordion/

1 - Description:

An expandable/collapsible content pane. Applicable when content must be displayed within limited space. Accordions are most commonly seen in the stacked vertical style on the web, but a horizontal accordion, where clickable tabs are rotated 90 degress to the left, should also be considered. We'd need to determine how to display the text for a horizonal accordion since rotating text is not possible in HTML and stacking each letter of the label on a separate line looks odd.

An accordion doesn't allow more than one content panel to be open at the same time, and it takes a lot of effort to do that. If you are looking for a widget that allows more than one content panel to be open, don't use this.  

2 - Visual Design:

3 - Functional Specifications/Requirements:

An accordion consists of a list of header/content pairs. Headers are always visible, while at most one content panel is visible. Switching between content panels works by clicking headers or navigating with the keyboard - when the accordion has focus, key up/down change focus between headers, enter activates the content of the selected header.

Options

• active (integer, boolean, default: 0)
• the zero-based index of the panel that is active (open).
• negative values select panels going backward from the last panel
• when collapsible: true, active: false closes the accordion, otherwise nothing happens
• animate (mixed, default: {})
• string; name of easing to use with default duration
• number, duration in milliseconds with default easing 
• object with easing and duration options
• can also contain a down option with any of the above options
• "down" animations occur when the panel being activated has a lower index than the currently active panel 
• null/false disables animation 
• collapsible (boolean, default: false)
• there can be only one panel open at once; for collapsible:true, all panels can be closed, otherwise exactly one must be open
• disabled (boolean, default: false)
• when disabled, the open panel will remain open and no other planel can be activated 
• event (string, default: "click")
• "mouseover" changes the accordion to a hover accordion (probably the only useful alternative)
• header (string, default: "> li > :first-child,> :not(li):even")
• must be a selector that applies to the accordion container element, via .find()
• the default covers both ul/li accordions, as well as flat structures like dl/dt/dd
• heightStyle (string, default "auto")
• controls the height of the accordion and each panel
• possible values:
• auto: all panels will be set to the height of the tallest panel
• fill: expand to the available height based on the accordion's parent height
• content: each panel will be only as tall as its content
• icons (hash)
• refers to CSS classes that must match an icon as defined by UI CSS framework:
• header (string, default: "ui-icon-triangle-1-e")
• activeHeader (string, default: "ui-icon-triangle-1-s")

Methods

• refresh
• Recomputes panel dimensions

Events

• beforeActivate (event: [depends on event option])
• triggered directly after a panel is activated
• can be cancelled to prevent the panel from activating 
• ui object:
• newHeader (object[jQuery])
• oldHeader (object[jQuery])
• newPanel (object[jQuery])
• oldPanel (object[jQuery]) 
• activate (event: none)
• triggered after the accordion panel has been activated (after animation completes)
• ui object:
• newHeader (object[jQuery])
• oldHeader (object[jQuery])
• newPanel (object[jQuery])
• oldPanel (object[jQuery])

Keyboard

• When focus is on a header: 
• UP/LEFT - Move focus to the previous header. If on first header, moves focus to last header.
• DOWN/RIGHT - Move focus to the next header. If on last header, moves focus to first header.
• HOME - Move focus to the first header.
• END - Move focus to the last header.
• SPACE/ENTER - Activate panel associated with focused header.
• When focus is in a panel:
• CTRL+UP - Move focus to associated header. 

Accessibility

• Follows ARIA best practices, with the following exceptions:
• aria-multiselectable is not set to true, since we do not allow multiple open panels.
• ctrl+page up/down is not supported because of interference with browser shortcuts, as mentioned in the best practices.
• Added aria-controls on the headers. 
• Notes
• Orca starts in caret navigation mode by default, which breaks arrow navigation. The user must press Orca + F12 to switch to Gecko's navigation mode in order to get proper arrow navigation. 
• Issues:

• Widget icons indicating expanded/collapsed state are invisible in high contrast mode
• Unable to see focus indication; items have color change on focus, but is lost in high contrast mode.
• JAWS 11 sometimes announces links for acordion headers, sometimes tabs. Problem with reading tab panel content when a link is activated as JAWS goes into forms mode.

4 - Markup & Style:

(only used prior to implementation)

5 - Latest version of plugin:

http://view.jqueryui.com/master/demos/accordion/default.html

6 - Open issues being discussed