amp-iframe
Description
Displays an iframe.
Required Scripts
<script async custom-element="amp-iframe" src="https://cdn.ampproject.org/v0/amp-iframe-1.0.js"></script>
<script async custom-element="amp-iframe" src="https://cdn.ampproject.org/v0/amp-iframe-1.0.js"></script> <link rel="stylesheet" href="https://cdn.ampproject.org/v0/amp-iframe-1.0.css">
Supported Layouts
Usage
Displays an AMP valid iframe. amp-iframe
has several important differences from vanilla iframes that are
designed to make it more secure and avoid AMP files that are dominated by a single iframe:
- An
amp-iframe
may not appear close to the top of the document (except for iframes that useplaceholder
as described below). The iframe must be either 600 px away from the top or not within the first 75% of the viewport when scrolled to the top, whichever is smaller. - By default, an
amp-iframe
is sandboxed (see details). - An
amp-iframe
must only request resources via HTTPS, from a data-URI, or via thesrcdoc
attribute. - An
amp-iframe
must not be in the same origin as the container unless they do not allowallow-same-origin
in thesandbox
attribute. See the "Iframe origin policy" doc for further details on allowed origins for iframes.
<amp-iframe width="200" height="100" sandbox="allow-scripts allow-same-origin" layout="responsive" src="https://www.google.com/maps/embed/v1/place?key=AIzaSyAyAS599A2GGPKTmtNr9CptD61LE4gN6oQ&q=iceland" > </amp-iframe>
Migrating from 0.1
Unlike 0.1
, the experimental 1.0
version of amp-iframe
has deprecated the frameborder
attribute. Use the CSS border
property to control <amp-iframe>
borders.
Use existing AMP components instead of amp-iframe
The amp-iframe
component should be considered a fallback if the required user
experience is not possible by other means in AMP, that is, there's not already
an existing AMP component for the use case. This is because there are many
benefits to using an AMP component tailored for a specific use-case such as:
- Better resource management and performance
- Custom components can provide built-in placeholder images in some cases. This means getting, say, the right video thumbnail before a video loads, and reduces the coding effort to add a placeholder manually.
- Built-in resizing. This means that iframe content with unpredictable size can more often appear to the user as if it were native to the page, rather than in a scrollable frame
- Other additional features can be built in (for instance, auto-play for video players)
Usage of amp-iframe
for advertising
amp-iframe
must not be used for the primary purpose of displaying
advertising. It is OK to use amp-iframe
for the purpose of displaying videos,
where part of the videos are advertising. This AMP policy may be enforced by not
rendering the respective iframes.
Advertising use cases should use
amp-ad
instead.
The reasons for this policy are that:
amp-iframe
enforces sandboxing and the sandbox is also applied to child iframes. This means landing pages may be broken, even if the ad itself appears to work.amp-iframe
does not provide any mechanism to pass configuration to the iframe.amp-iframe
has no fully iframe controlled resize mechanism.- Viewability information may not be available to
amp-iframe
.
Standalone use outside valid AMP documents
Bento allows you to use AMP components in non-AMP pages without needing to commit to fully valid AMP. You can take these components and place them in implementations with frameworks and CMSs that don't support AMP. Read more in our guide Use AMP components in non-AMP pages.
To find the standalone version of amp-iframe
, see bento-iframe
.
Iframe with placeholder
It is possible to have an amp-iframe
appear at the top of a document when the
amp-iframe
has a placeholder
element as shown in the example below.
- The
amp-iframe
must contain an element with theplaceholder
attribute, (for instance anamp-img
element) which would be rendered as a placeholder until the iframe is ready to be displayed. - Iframe readiness can be known by listening to
onload
of the iframe or anembed-ready
postMessage
, which would be sent by the iframe document, whichever comes first.
The following example shows an iframe with a placeholder:
<amp-iframe width="300" height="300" layout="responsive" sandbox="allow-scripts allow-same-origin" src="https://foo.com/iframe" > <amp-img layout="fill" src="https://foo.com/foo.png" placeholder></amp-img> </amp-iframe>
The following example shows an iframe with an embed-ready request:
window.parent.postMessage( { sentinel: 'amp', type: 'embed-ready', }, '*' );
Iframe resizing
An amp-iframe
must have static layout defined as is the case with any other
AMP element. However, it's possible to resize an amp-iframe
at runtime. To do
so:
- The
amp-iframe
must be defined with theresizable
attribute. - The
amp-iframe
must have anoverflow
child element. This element can typically be adiv
. However, if theamp-iframe
is child of ap
element, it is recommended to use aspan
orbutton
(to eliminate issues caused byp
element's phrasing content). - The
amp-iframe
must set theallow-same-origin
sandbox attribute. - The iframe document must send an
embed-size
request as a window message. - The
embed-size
request will be denied if the request height is less than a certain threshold (100px).
Notice that resizable
overrides the value of scrolling
to no
.
The following example shows amp-iframe
with an overflow
element:
<amp-iframe width="300" height="300" layout="responsive" sandbox="allow-scripts allow-same-origin" resizable src="https://foo.com/iframe" > <div overflow tabindex="0" role="button" aria-label="Read more"> Read more! </div> </amp-iframe>
The following example shows an iframe resize request:
window.parent.postMessage( { sentinel: 'amp', type: 'embed-size', height: document.body.scrollHeight, }, '*' );
Once this message is received, the AMP runtime tries to accommodate the request
as soon as possible, but it takes into account where the reader is currently
reading, whether the scrolling is ongoing and any other UX or performance
factors. If the runtime cannot satisfy the resize request, the amp-iframe
will
show an overflow
element. Clicking on the overflow
element will immediately
resize the amp-iframe
since it's triggered by a user action.
Here are some factors that affect how fast the resize will be executed:
- Whether the resize is triggered by the user action.
- Whether the resize is requested for a currently active iframe.
- Whether the resize is requested for an iframe below the viewport or above the viewport.
Iframe viewability
Iframes can send a send-intersections
message to their parents to start
receiving IntersectionObserver
style
change records
of the iframe's intersection with the parent viewport.
In the following examples, we assume the script is in the created iframe, where
window.parent
is the top window. If the script lives in a nested iframe,
change window.parent
to the top AMP window.
The following example shows an iframe send-intersections
request:
window.parent.postMessage( { sentinel: 'amp', type: 'send-intersections', }, '*' );
The iframe can listen to an intersection
message from the parent window to
receive the intersection data.
The following example shows an iframe send-intersections
request:
function isAmpMessage(event, type) { return ( event.source == window.parent && event.origin != window.location.origin && event.data && event.data.sentinel == 'amp' && event.data.type == type ); } window.addEventListener('message', function (event) { if (!isAmpMessage(event, 'intersection')) { return; } event.data.changes.forEach(function (change) { console.log(change); }); });
The intersection message would be sent by the parent to the iframe in the format of IntersectionObserver entry wheneve there is intersectionRatio change across thresholds [0, 0.05, 0.1, ... 0.9, 0.95, 1].
Attributes
src
The src
attribute behaves mainly like on a standard iframe with one exception:
the #amp=1
fragment is added to the URL to allow source documents to know that
they are embedded in the AMP context. This fragment is only added if the URL
specified by src
does not already have a fragment.
srcdoc
, frameborder
, allowfullscreen
, allowpaymentrequest
, allowtransparency
, and referrerpolicy
These attributes should all behave like they do on standard iframes.
If frameborder
is not specified, by default, it will be set to 0
.
sandbox
Iframes created by amp-iframe
always have the sandbox
attribute defined on
them. By default, the value is empty, which means that they are "maximum
sandboxed". By setting sandbox
values, one can opt the iframe into being less
sandboxed. All values supported by browsers are allowed. For example, setting
sandbox="allow-scripts"
allows the iframe to run JavaScript, or
sandbox="allow-scripts allow-same-origin"
allows the iframe to run JavaScript,
make non-CORS XHRs, and read/write cookies.
If you are iframing a document that was not specifically created with sandboxing
in mind, you will most likely need to add allow-scripts allow-same-origin
to
the sandbox
attribute and you might need to allow additional capabilities.
Note also, that the sandbox applies to all windows opened from a sandboxed
iframe. This includes new windows created by a link with target=_blank
(add
allow-popups
to allow this to happen). Adding allow-popups-to-escape-sandbox
to the sandbox
attribute, makes those new windows behave like non-sandboxed
new windows. This is likely most of the time what you want and expect.
Unfortunately, as of this writing, allow-popups-to-escape-sandbox
is supported
by Chrome, Firefox, Safari and Opera but not Edge.
See the docs on MDN
for further details on the sandbox
attribute.
Common attributes
amp-iframe
includes the
common attributes
extended to AMP components.
Analytics
We strongly recommend using
amp-analytics
for
analytics purposes, because it is significantly more robust, complete and an
efficient solution which can be configured for a wide range of analytics
vendors.
AMP only allows a single iframe that is used for analytics and tracking purposes, per page. To conserve resources, these iframes will be removed from the DOM 5 seconds after they loaded, which should be sufficient time to complete whatever work is needed to be done.
Iframes are identified as tracking/analytics iframes if they appear to serve no direct user purpose such as being invisible or small.
Validation
See amp-iframe
rules in the AMP validator specification.
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