eBay MIND Patterns
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Infotip
Reveals helpful information about a nearby non-interactive element or region of a page.
Helping user with form
Introduction
Infofip is a click-activated flyout. It discloses supplementary or advisory content about an existing onscreen element or region.
Thematically, you can think of infotip content fulfilling the same role as footnotes in a page.
Infotip is a composite pattern containing a button and an overlay. The button toggles the visibility of the overlay. The overlay contains the help content.
Updated: October 28th, 2020 (minor updates to Best Practices)
Working Examples
Terminology
We use the following terminology when discussing this pattern.
- infotip: the pattern as a whole, comprised of the following sub-parts
- button: the button that hosts the overlay
- overlay/bubble: the overlay that contains the tip
- pointer: the visual affordance that "points" to the button
- tip: the tip content
- expanded: an infotip with expanded overlay
- collapsed: an infotip with collapsed overlay
Best Practices
On desktop screens, overlay must not be modal. On smaller screens, the overlay may be implemented as a modal dialog.
Button must not have overlay content duplicated within an
aria-describedby attribute.Button must not have
aria-haspopup attribute. Despite the name of this property, it is actually intended specifically for a Menu.The infotip must remain expanded until explicitly closed by user.
Overlay should be hidden by default.
Overlay content should be no more than one or two paragraphs in length. For lengthier content, consider instead using a dialog.
Interaction Design
This section provides the pattern interaction design for keyboard, screen reader & pointing devices.
Keyboard
Button must be keyboard focusable.
Activating button must toggle the expanded state of the overlay. Keyboard focus should remain on the button.
If overlay contains focusable elements, tab order must flow directly from button to first of those elements.
If the overlay has no focusable elements, tab order must flow directly to next page control.
Screen Reader
Button purpose must be announced (e.g. 'Help).
Button state must be announced (i.e. expanded or collapsed).
Reading order must flow directly from button into overlay.
Expanded state must be announced after expanded.
Pointer
Invoking button must toggle the expanded state of the overlay.
Developer Guide
This implementation will get us quickly up and running with the accessibility requirements of an infotip.
HTML
The goal of our content layer is to add the button and overlay. The structure and DOM positioning of these elements is of utmost importance so that keyboard tabbing order and screen reader both naturally flow into the overlay.
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<span class="infotip" id="infotip-0">
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<button class="infotip__host" aria-controls="infotip-0-overlay" aria-expanded="false" aria-label="Help" type="button"></button>
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<span class="infotip__live-region" aria-live="off">
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<div class="infotip__overlay" id="infotip-0-overlay">
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<!-- overlay content -->
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</div>
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</span>
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</span>
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Notice placement of the button directly before the live-region element. This allows natural tab order flow and screen reading order from the button into the overlay.
The live-region property is set to "off". This is a matter of preference. Some people prefer the new content to announce when it appears, using a setting of "polite". At eBay we have this set to off and we rely on the
aria-expanded state as being the affordance.CSS
The goal of the CSS layer is to hide or show the overlay depending on the aria-expanded state.
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.infotip {
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position: relative;
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}
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.infotip__overlay {
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display: none;
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position: absolute;
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white-space: nowrap;
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z-index: 1;
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}
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.infotip__host[aria-expanded=true] ~ .infotip__live-region .infotip__overlay {
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display: block;
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}
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The overlay must have
display: none when in a collapsed state to ensure that screen readers cannot access the overlay content. You may also wish to leverage the hidden property instead.For a progressive enhancement approach, you may choose to have all infotip content visible by default, and then hide it when JavaScript becomes available. This can however result in a flash of unstyled content (FOUC).
JavaScript
CSS alone cannot change the value of an aria attribute; we require JavaScript. Fortunately, the makeup-expander module can handle this behaviour for us in just a few lines of code.
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const Expander = require('makeup-expander');
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​
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const widget = new Expander(widgetEl, {
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contentSelector: '.infotip__content',
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expandOnClick: true,
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collapseOnClick: true,
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hostSelector: '.infotip__host'
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});
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Clicking the button with mouse or keyboard will now toggle the aria-expanded state of the button.
Animations are also possible of course, but fall outside the scope of accessibility.
Utilities
The following JavaScript modules may assist you in creation of an infotip pattern:
- ​makeup-expander: handles some basic accessibility for an element that expands and collapses another element.
ARIA Reference
aria-live
Informs assistive technology to announce the overlay contents whenever the button changes from collapsed to expanded.
role=button
Informs assistive technology that our anchor element now behaves like a button instead of a link.
aria-label
Provides a more accessible button label for assistive technology, over-riding the inner text of the anchor element.
aria-expanded
Informs assistive technology of the expanded state of the button.
FAQ
This is different to the way BootStrap 'Popovers' work. Why?
The fundamental difference is that the Bootstrap Popovers get their content from a data attribute, whereas the pattern presented here gets it's content from an actual element. This allows us to more easily place HTML such as hyperlinks & images inside of our popovers and, unlike Bootstrap, the popover content can be fully accessible without JavaScript (assuming you choose to make the content visible by default).
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Last modified 1yr ago