amp-carousel
Description
Displays multiple similar pieces of content along a horizontal axis.
Required Scripts
<script async custom-element="amp-carousel" src="https://cdn.ampproject.org/v0/amp-carousel-0.2.js"></script>
Supported Layouts
Usage
A generic carousel for displaying multiple similar pieces of content along a horizontal axis; meant to be flexible and performant.
Each of the amp-carousel
component’s immediate children is considered an item
in the carousel. Each of these nodes may also have arbitrary HTML children.
The carousel consists of an arbitrary number of items, as well as optional
navigational arrows to go forward or backwards. For type="slides"
, the arrows
moves one item at a time. For type="carousel"
, the arrows move one carousel's
width forwards or backwards at a time.
The carousel advances between items if the user swipes or clicks an optional navigation arrow.
<amp-carousel width="450" height="300" layout="responsive" type="slides" role="region" aria-label="Basic carousel" > <amp-img src="/static/inline-examples/images/image1.jpg" width="450" height="300" ></amp-img> <amp-img src="/static/inline-examples/images/image2.jpg" width="450" height="300" ></amp-img> <amp-img src="/static/inline-examples/images/image3.jpg" width="450" height="300" ></amp-img> </amp-carousel>
Differences from <amp-carousel>
0.1
autoplay
is allowed ontype="carousel"
loop
is allowed ontype="carousel"
Migration Notes
- Update the required script from
amp-carousel-0.1
toamp-carousel-0.2
. - Ensure any CSS for positioning next/previous arrows is still valid. See the styling for more information on arrow positioning.
- Ensure any CSS used to style the carousel is still valid. The internal DOM structure of
<amp-carousel>
0.2 differs from 0.1, effecting CSS selectors targeting internal elements such asamp-carousel > div
. Any selectors using the.amp-class-name
format should still work. - NOTE: Support for
amp-carousel-0.1
is limited, with the intent to deprecate in the future.
Advancing to a specific slide
Setting a method for the on
attribute on an element to
tap:carousel-id.goToSlide(index=N)
will, on user tap or click, advance a
carousel with the "carousel-id" ID to the slide at index=N (the first slide is
at index=0, the second slide is at index=1, and so on).
In the following example, we have a carousel of three images with preview buttons below the carousel. When a user clicks one of the buttons, the corresponding carousel item displays.
<amp-carousel id="carousel-with-preview" width="450" height="300" layout="responsive" type="slides" role="region" aria-label="Carousel with slide previews" > <amp-img src="/static/inline-examples/images/image1.jpg" width="450" height="300" layout="responsive" alt="apples" ></amp-img> <amp-img src="/static/inline-examples/images/image2.jpg" width="450" height="300" layout="responsive" alt="lemons" ></amp-img> <amp-img src="/static/inline-examples/images/image3.jpg" width="450" height="300" layout="responsive" alt="blueberries" ></amp-img> </amp-carousel> <div class="carousel-preview"> <button on="tap:carousel-with-preview.goToSlide(index=0)"> <amp-img src="/static/inline-examples/images/image1.jpg" width="60" height="40" alt="apples" ></amp-img> </button> <button on="tap:carousel-with-preview.goToSlide(index=1)"> <amp-img src="/static/inline-examples/images/image2.jpg" width="60" height="40" alt="lemons" ></amp-img> </button> <button on="tap:carousel-with-preview.goToSlide(index=2)"> <amp-img src="/static/inline-examples/images/image3.jpg" width="60" height="40" alt="blueberries" ></amp-img> </button> </div>
Accessibility considerations for amp-carousel
Autoplaying, and particularly infinitely looping, carousels can be very distracting and confusing for users - especially for users with cognitive impairments. In general, we recommend avoiding autoplaying carousels. While autoplaying carousels stop once the user has interacted with the carousel, consider also adding an explicit "Play/Pause" control.
By default, the <amp-carousel>
is programmatically identified as a list when rendered (using role="list"
on the container element, and role="listitem"
on each item). However, for <amp-carousel type="slides">
, no specific role
is currently provided. As a result, it will not be obvious for assistive technology users reading/navigating through a page when they reach a carousel. We recommend including an explicit role="region"
and a descriptive aria-label
(either a generic aria-label="Carousel"
or a more descriptive label such as aria-label="Latest news items"
) to <amp-carousel>
.
Currently, an <amp-carousel type="slides">
carousel is declared as an ARIA live region (using aria-live="polite"
), meaning that every time a new slide is shown, the entire content of the slide is announced by assistive technologies (such as screen readers). Due to the way carousels are initially rendered, this can also result in the carousel's content being announced in its entirety when a page is loaded. This also means that pages that contain an autoplay
carousel will continuously announce whenever a slide auto-advances. There is currently no work-around for this issue.
Attributes
type
Specifies the display type for the carousel items, which can be:
- carousel (default): All slides are shown and are scrollable horizontally. Each slide may specify a different width using CSS.
- slides: Shows a single slide at a time, with each slide snapping into place as the user swipes.
controls (optional)
Permanently displays left and right arrows for the user to navigate carousel items on mobile devices. By default, navigational arrows disappear after the user swipes to another slide on mobile.
The visibility of arrows can also be controlled via styling, and a media query can be used to only display arrows at certain screen widths. On desktop, arrows are always displayed unless only a single child is present.
data-next-button-aria-label (optional)
Sets the aria-label for the amp-carousel-button-next
. If no value is given,
the aria-label defaults to 'Next item in carousel'.
data-prev-button-aria-label (optional)
Sets the aria-label for the amp-carousel-button-prev
. If no value is given,
the aria-label defaults to 'Previous item in carousel'.
data-button-count-format (optional)
A format string that looks like (%s of %s)
, used as a suffix to the aria-label
for amp-carousel-button-next
/amp-carousel-button-prev
. This provides
information to users using a screen reader on their progress through the
carousel. If no value is given, this defaults to (%s of %s)
.
autoplay (optional)
Regularly advances to the next slide without user interaction. If the user manually changes slides, then autoplay is stopped.
If present without a value:
- By default, advances a slide in 5000 millisecond intervals (5 seconds); this can be overridden by the
delay
attribute. - Requires at least 2 slides for autoplay to occur.
If present with a value:
- Stops autoplaying after the requisite number of loops are made.
delay (optional)
Specifies the duration (in milliseconds) to delay advancing to the next slide
when autoplay
is enabled. Note that the minimum allowed value for delay is
1000 milliseconds.
loop (optional)
Allows the user to advance past the first item or the final item. There must be at least 3 slides for looping to occur.
The example below displays a slide carousel with controls, looping, and delayed autoplay.
<amp-carousel type="slides" width="450" height="300" controls loop autoplay delay="3000" data-next-button-aria-label="Go to next slide" data-previous-button-aria-label="Go to previous slide" role="region" aria-label="Looping carousel"> <amp-img src="/static/inline-examples/images/image1.jpg" width="450" height="300"></amp-img> <amp-img src="/static/inline-examples/images/image2.jpg" width="450" height="300"></amp-img> <amp-img src="/static/inline-examples/images/image3.jpg" width="450" height="300"></amp-img> </amp-carousel>
slide (optional)
Specifies what index should be shown when the carousel is first rendered. This
can be updated with
amp-bind
to change which
index is shown.
common attributes
This element includes common attributes extended to AMP components.
Actions
goToSlide(index=INTEGER)
Advances the carousel to a specified slide index.
toggleAutoplay(toggleOn=true|false)
Toggle the carousel's autoplay status. toggleOn
is optional.
Events
slideChange
Fired when the carousel's current slide changes.
// Slide number. Event.index
Styling
- You may use the
amp-carousel
element selector to style it freely. - You may use the
.amp-carousel-slide
class selector to target carousel items. - The visual state of an
amp-carousel
button when it's disabled is hidden. - By default,
.amp-carousel-button
uses an inlined SVG as the background-image of the buttons. You may override this with your own SVG or image as in the example below.
Example: Default .amp-carousel-button
inlined SVG
.amp-carousel-button-prev { background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg xmlns="http://www.w3.org/2000/svg" width="18" height="18" fill="%23fff"%3E%3Cpath d="M15 8.25H5.87l4.19-4.19L9 3 3 9l6 6 1.06-1.06-4.19-4.19H15v-1.5z"/%3E%3C/svg%3E'); }
Example: Overriding the default .amp-carousel-button
inlined SVG
.amp-carousel-button-prev { background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg xmlns="http://www.w3.org/2000/svg" width="18" height="18" fill="%23fff"%3E%3Cpath d="M11.56 5.56L10.5 4.5 6 9l4.5 4.5 1.06-1.06L8.12 9z" /%3E%3C/svg%3E'); }
Note that the SVG content needs to have certain characters, including <
, >
and #
encoded. This can be done using a tool like SVGO or using encodeURIComponent
.
- You can position the carousel buttons using align-self and/or relative positioning. Note that the carousel arrows are automatically flipped in RTL, so you should not change their flex order.
.amp-carousel-button-prev { position: relative; bottom: 20px; align-self: flex-end; }
Validation
See amp-carousel rules in the AMP validator specification.
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