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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>
Web App Manifest
</title>
<script src="https://www.w3.org/Tools/respec/respec-w3c-common" class=
"remove"></script>
<script class='remove'>
var respecConfig = {
previousPublishDate: "2013-12-17",
specStatus: 'WD',
shortName: 'appmanifest',
subtitle: 'Living Document',
prevVersion: 'FPWD',
previousMaturity: "WD",
editors: [{
name: "Marcos Caceres",
company: "Mozilla Corporation",
companyURL: "https://mozilla.org/",
w3cid: 39125
}, {
name: "Kenneth Rohde Christiansen",
company: "Intel Corporation",
companyURL: "https://intel.com/",
w3cid: 57705
}, {
name: "Mounir Lamouri",
company: "Google Inc.",
companyURL: "https://google.com/",
w3cid: 45389
}, {
name: "Anssi Kostiainen",
company: "Intel Corporation",
companyURL: "https://intel.com/",
w3cid: 41974
}, {
name: "Rob Dolin",
company: "Microsoft Corporation",
companyURL: "https://microsoft.com/",
w3cid: 60712
}, {
name: "Matt Giuca",
company: "Google Inc.",
companyURL: "https://google.com/",
w3cid: 91260
}],
wg: 'Web Platform Working Group',
wgURI: 'https://www.w3.org/WebPlatform/WG/',
wgPublicList: 'public-webapps',
wgPatentURI: 'https://www.w3.org/2004/01/pp-impl/83482/status',
otherLinks: [{
key: "Implementation status",
data: [{
value: "Blink",
href: "https://www.chromestatus.com/feature/6488656873259008"
}, {
value: "EdgeHTML",
href: "https://developer.microsoft.com/en-us/microsoft-edge/platform/status/webapplicationmanifest/"
}, {
value: "Gecko",
href: "https://bugzil.la/997779"
}, {
value: "WebKit",
href: "https://webkit.org/b/158205"
}]
}],
github: "https://github.com/w3c/manifest/",
};
</script>
</head>
<body>
<section id='abstract'>
<p>
This specification defines a JSON-based manifest file that provides
developers with a centralized place to put metadata associated with a
web application. This metadata includes, but is not limited to, the web
application's name, links to icons, as well as the preferred URL to
open when a user launches the web application. The manifest also allows
developers to declare a default orientation for their web application,
as well as providing the ability to set the display mode for the
application (e.g., in fullscreen). Additionally, the manifest allows a
developer to "scope" a web application to a URL. This restricts the
URLs to which the manifest is applied and provides a means to "deep
link" into a web application from other applications.
</p>
<p>
Using this metadata, user agents can provide developers with means to
create user experiences that are more comparable to that of a native
application.
</p>
<p>
This specification also defines the <code>manifest</code> link type as
a declarative means to associate a document with a manifest.
</p>
</section>
<section id="sotd">
<div class="warning">
<p>
Implementors need to be aware that this specification is not stable.
However, aspects of this specification are shipping in at least one
browser (see links to implementation status at the top of this
document). <strong>Implementors who are not taking part in the
discussions will find the specification changing out from under them
in incompatible ways.</strong> Vendors interested in implementing
this specification before it eventually reaches the Candidate
Recommendation phase should <a href=
"https://github.com/w3c/manifest/issues">subscribe to the repository
on GitHub</a> and take part in the discussions.
</p>
</div>
</section>
<section class="informative">
<h2>
Usage Examples
</h2>
<p>
This section shows how developers can make use of the various features
of this specification.
</p>
<section class="informative">
<h3>
Example manifests
</h3>
<p>
The following shows a very simple <a>manifest</a>.
</p>
<pre class="example json" title="very simple manifest">
{
"name": "Donate App",
"description": "This app helps you donate to worthy causes.",
"icons": [{
"src": "images/icon.png",
"sizes": "192x192"
}]
}
</pre>
<p>
The following shows a more typical <a>manifest</a>.
</p>
<pre class="example json" title="typical manifest">
{
"lang": "en",
"dir": "ltr",
"name": "Super Racer 3000",
"description": "The ultimate futuristic racing game from the future!",
"short_name": "Racer3K",
"icons": [{
"src": "icon/lowres.webp",
"sizes": "64x64",
"type": "image/webp"
},{
"src": "icon/lowres.png",
"sizes": "64x64"
}, {
"src": "icon/hd_hi",
"sizes": "128x128"
}],
"scope": "/racer/",
"start_url": "/racer/start.html",
"display": "fullscreen",
"orientation": "landscape",
"theme_color": "aliceblue",
"background_color": "red",
"serviceworker": {
"src": "sw.js",
"scope": "/racer/",
"update_via_cache": "none"
},
"screenshots": [{
"src": "screenshots/in-game-1x.jpg",
"sizes": "640x480",
"type": "image/jpeg"
},{
"src": "screenshots/in-game-2x.jpg",
"sizes": "1280x920",
"type": "image/jpeg"
}]
}
</pre>
</section>
<section class="informative">
<h3>
Using a <code>link</code> element to link to a manifest
</h3>
<p>
Example of using a <code>link</code> element to associate a website
with a <a>manifest</a>. The example also shows how to use [[!HTML]]'s
<code>link</code> and <code>meta</code> elements to give the web
application a fallback name and set of icons.
</p>
<pre class="example html" title="linking to a manifest">
<!doctype>
<html>
<title>Racer 3K</title>
<!-- Startup configuration -->
<link rel="manifest" href="manifest.webmanifest">
<!-- Fallback application metadata for legacy browsers -->
<meta name="application-name" content="Racer3K">
<link rel="icon" sizes="16x16 32x32 48x48" href="lo_def.ico">
<link rel="icon" sizes="512x512" href="hi_def.png">
</pre>
</section>
</section>
<section>
<h2>
Installable web applications
</h2>
<p>
A common use case of a manifest is for a user agent to <dfn data-lt=
"installing|installed|installation" data-export="">install</dfn> a web
application; whereby the user agent provides the end-user with a means
of instantiating a new <a>top-level browsing context</a> that has the
manifest's members <a>applied</a> to it. That is, the manifest's
members, or their defaults, are in effect on the <a>top-level browsing
context</a>. This distinguishes an installed web application from a
traditional bookmark, as opening a web page from a traditional bookmark
will not have the manifest's properties <a>applied</a> to it.
</p>
<p>
For example, on user agents that support installation, a web
application could be presented and launched in a way that, to the
end-user, is indistinguishable from native applications: such as
appearing as a labeled icon on the home screen, launcher, or start
menu. When launched, the manifest is <a>applied</a> by the user agent
to the <a>top-level browsing context</a> prior to the <a>start URL</a>
being loaded. This gives the user agent an opportunity to apply the
relevant values of the manifest, possibly changing the <a>display
mode</a> and screen orientation of the web application. Alternatively,
and again as an example, the user agent could <a>install</a> the web
application into a list of bookmarks within the user agent itself.
</p>
<section data-dfn-for="AppBannerPromptOutcome">
<h4>
<code>AppBannerPromptOutcome</code> enum
</h4>
<pre class="idl">
enum AppBannerPromptOutcome {
"accepted",
"dismissed"
};
</pre>
<p>
The <dfn>AppBannerPromptOutcome</dfn> enum's values represent the
outcomes from <a data-lt="presents an install prompt">presenting the
end-user with an install prompt</a>.
</p>
<dl data-dfn-for="AppBannerPromptOutcome">
<dt>
<dfn>accepted</dfn>:
</dt>
<dd>
The end-user indicated that they would like the user agent to
<a>install</a> the web application.
</dd>
<dt>
<dfn>dismissed</dfn>:
</dt>
<dd>
The end-user dismissed the install prompt.
</dd>
</dl>
</section>
<section>
<h3>
Authority of the manifest's metadata
</h3>
<p>
When a <a>manifest</a> is linked from a <code>Document</code>, it
indicates to the user agent that the metadata is
<dfn>authoritative</dfn>: that is, the user agent SHOULD use the
metadata of the manifest instead of the one in the
<code>Document</code>. However, in cases where metadata is missing,
or in error, a user agent MAY fallback to the <code>Document</code>
to find suitable replacements for missing manifest members (e.g.,
using <code>application-name</code> in place of
<code>short_name</code>).
</p>
</section>
<section data-link-for="WebAppManifest">
<h3>
Application's name
</h3>
<p>
The <dfn>application's name</dfn> is derived from either the
<a>name</a> member or <a>short_name</a> member (if either is present)
- otherwise, it is generated by the user agent or provided by the
end-user.
</p>
<p>
When either member is missing from the manifest, a user agent MAY use
the <a>name</a> member as a fallback for the <a>short_name</a> member
or vice versa.
</p>
<p>
If the <a>name</a> and <a>short_name</a> members are undefined, the
user agent SHOULD assign a default name (e.g., "Untitled").
Alternatively, a user agent MAY allow the end-user to input some text
that can serve as the <a>application's name</a>.
</p>
<p>
When both the <a>name</a> and <a>short_name</a> members are present,
it is left up to implementations to decide which member is best
suited for the space available (e.g., the <a>short_name</a> member
might be better suited for the space available underneath an icon).
</p>
</section>
<section>
<h3>
Installation process
</h3>
<p>
An <dfn>installation process</dfn> is an attempt by the user agent to
<a>install</a> a web application. The details of such a process
(i.e., the display of an install <abbr>UI</abbr>, and any resulting
<abbr>IO</abbr> operations of the host <abbr>OS</abbr>) are left up
to implementers. Implementers need to be aware that there are
<a href="#installation-sec">privacy and security considerations</a>
that directly relate to the <a>installation process</a>.
</p>
<p>
For the purpose of this specification, the <dfn>installation
succeeded</dfn> once the <a>installation process</a> succeeds in
<a>installing</a> the web application (e.g., an icon was successfully
placed onto the device's homescreen). If the end-user cancels the
installation process (even if they <a>manually</a> triggered it, and
then changed their minds), then the <dfn>installation was
canceled</dfn>. Otherwise, the <dfn>installation failed</dfn>.
Reasons for installation failure can include, for example, the OS
denying permission to the user agent to add an icon to the homescreen
of the device and the end-user rejecting the installation.
</p>
<p>
The <dfn>steps to install the web application</dfn> are given by the
following algorithm:
</p>
<ol>
<li>Let <var>window</var> be the <code>Window</code> object of the
<a>top-level browsing context</a> for which the user agent will
attempt installation.
</li>
<li>Then, <a>in parallel</a>:
<ol>
<li>Instantiate an <a>installation process</a>.
</li>
<li>Let <a>manifest</a> and <a>manifest URL</a> be the result of
<a>obtaining the manifest</a>.
</li>
<li>If <a>obtaining the manifest</a> results in an error, a user
agent can, at this point, fall back to using the <a>top-level
browsing context</a> <code>Document</code>'s metadata to populate
an <a>installation process</a>'s UI.
</li>
<li>If <a>obtaining the manifest</a> succeeds, and the result of
running <a>processing the serviceworker member</a> with
<a>manifest</a> returns a valid <var>registration</var>, a user
agent can at this point
<ol>
<li>Let <var>client</var> be the <a>top-level browsing
context</a> <code>Document</code>'s <a href=
"https://html.spec.whatwg.org/multipage/webappapis.html#relevant-settings-object">
relevant settings object</a>, or <code>null</code> if
unavailable.
</li>
<li>Invoke <a>Start Register</a> with <var>scope</var> and
<var>src</var> members of the <var>registration</var>, a new
<var>promise</var>, <var>client</var>, <a>manifest URL</a>,
plus the <var>type</var> and <var>update_via_cache</var>
members of the <var>registration</var>,
</li>
</ol>in which case the state of the settled <var>promise</var>
determines whether the <a>installation succeeded</a> or not.
</li>
<li>If the <a>installation succeeded</a>, <a>queue a task</a> on
the <a>application life-cycle task source</a> to <a>fire an
event</a> named <code>appinstalled</code> at the
<var>window</var> object.
</li>
</ol>
</li>
</ol>
</section>
<section>
<h2>
Install prompts
</h2>
<p>
There are multiple ways that the installation process can be
triggered:
</p>
<ul>
<li>An end-user can <dfn data-lt="manual installation">manually</dfn>
trigger the <a>installation process</a> through the user agent's
<abbr>UI</abbr>.
</li>
<li>The <a>installation process</a> can occur through an
<dfn>automated install prompt</dfn>: that is, a <abbr>UI</abbr> that
the user agent presents to the user when, for instance, there are
sufficient <a>installability signals</a> to warrant
<a>installation</a> of the web application.
</li>
<li>The <a>installation process</a> can occur through a
<dfn>site-triggered install prompt</dfn>: the site can
programmatically request that the user agent present an install
prompt to the user. The user agent MAY restrict the availability of
this feature to cases where, for instance, there are sufficient
<a>installability signals</a> to warrant <a>installation</a> of the
web application.
</li>
</ul>
<p>
Prior to presenting an <a>automated install prompt</a>, a user agent
MUST run the <a>steps to notify that an install prompt is
available</a>, to give the site the opportunity to prevent the
default action (which is to install the application). Alternatively,
the user agent MAY run the <a>steps to notify that an install prompt
is available</a> at any time, giving the site the opportunity to show
a <a>site-triggered install prompt</a> without automatically showing
the prompt.
</p>
<p>
In either case, when a user agent <dfn data-lt=
"present an install prompt|presenting an install prompt">presents an
install prompt</dfn>, the end-user's choice is represented either
"accepted" or "dismissed". These values are represented in the API of
this specification via the <a>AppBannerPromptOutcome</a> enum.
</p>
<p>
The <dfn>steps to notify that an install prompt is available</dfn>
are given by the following algorithm:
</p>
<ol>
<li>Wait until the <code>Document</code> of the <a>top-level browsing
context</a> is <a>completely loaded</a>.
</li>
<li>If there is already an <a>installation process</a> being
<a data-lt="present an install prompt">presented</a>, terminate this
algorithm.
</li>
<li>
<a>Queue a task</a> on the <a>application life-cycle task
source</a> to do the following:
<ol>
<li>Let <var>event</var> be a newly constructed
<a>BeforeInstallPromptEvent</a> named
<code>beforeinstallprompt</code>, with its
<code>cancelable</code> attribute initialized to true.
</li>
<li>Let <var>mayShowPrompt</var> be the result of <a>firing</a>
<var>event</var> at the <a>Window</a> object of the <a>top-level
browsing context</a>.
</li>
<li>If <var>mayShowPrompt</var> is true, then the user agent MAY,
<a>in parallel</a>, <a>request to present an install prompt</a>
with <var>event</var>.
</li>
</ol>
</li>
</ol>
</section>
<section>
<h3 id="installation-sec">
Privacy and security considerations
</h3>
<p>
During the <a>installation process</a>, it is RECOMMENDED that the
user agent allow the end-user to inspect the icon, name, <a>start
URL</a>, origin, etc. pertaining to a web application. This is to
give an end-user an opportunity to make a conscious decision to
approve, and possibly modify, the information pertaining to the web
application before installing it. This also gives the end-user an
opportunity to discern if the web application is spoofing another web
application, by, for example, using an unexpected icon or name.
</p>
<p>
It is RECOMMENDED that user agents prevent other applications from
determining which applications are installed on the system (e.g., via
a timing attack on the user agent's cache). This could be done by,
for example, invalidating from the user agent's cache the resources
linked to from the manifest (for example, icons) after a web
application is <a>installed</a> - or by using an entirely different
cache from that used for regular web browsing.
</p>
</section>
<section class="informative">
<h3>
Installability signals
</h3>
<p>
By design, this specification does not provide developers with an
explicit API to "install" a web application. Instead, a
<a>manifest</a> can serve as an <dfn data-lt=
"installability signals">installability signal</dfn> to a user agent
that a web application can be <a>installed</a>.
</p>
<p>
Examples of <a>installability signals</a> for a web application:
</p>
<ul>
<li>is <a>associated with a manifest</a> with at least a
<code>name</code> member and a suitable icon.
</li>
<li>is served over a secure network connection.
</li>
<li>has a sensible content security policy.
</li>
<li>is able to responsively adapt to display on a variety of screen
sizes, catering for both mobile and desktop.
</li>
<li>is able to function without a network connection.
</li>
<li>is repeatedly used by the end-user over some extended period of
time.
</li>
<li>has been explicitly marked by the user as one that they value and
trust (e.g., by bookmarking or "starring" it).
</li>
</ul>
<p>
This list is not exhaustive and some <a>installability signals</a>
might not apply to all user agents. How a user agent makes use of
these <a>installability signals</a> to determine if a web application
can be <a>installed</a> is left to implementers.
</p>
</section>
<section>
<h3>
Uninstallation
</h3>
<p>
User agents SHOULD provide a mechanism for the user to remove the
installed application.
</p>
<p>
It is RECOMMENDED that at the time of removal, the user agent also
present the user with an opportunity to revoke other persistent data
and settings associated with the application, such as permissions and
persistent storage.
</p>
</section>
</section>
<section>
<h2>
Installation Events
</h2>
<p>
DOM events <a>fired</a> by this specification use the <dfn>application
life-cycle task source</dfn>.
</p>
<section data-dfn-for="BeforeInstallPromptEvent" data-link-for=
"BeforeInstallPromptEvent">
<h3>
<dfn>BeforeInstallPromptEvent</dfn> Interface
</h3>
<div class="note">
The <a>beforeinstallprompt</a> event is somewhat misnamed, as it does
not necessarily signal that an <a>automated install prompt</a> will
follow (depending on the user agent, it might just be giving the site
the ability to trigger an install prompt). It is so named for
historical reasons.
</div>
<pre class="idl">
[Constructor, Exposed=Window]
interface BeforeInstallPromptEvent : Event {
Promise<PromptResponseObject> prompt();
};
dictionary PromptResponseObject {
AppBannerPromptOutcome userChoice;
};
</pre>
<p>
The <a>BeforeInstallPromptEvent</a> is dispatched when the site is
allowed to present a <a>site-triggered install prompt</a>, or prior
to the user agent presenting an <a>automated install prompt</a>. It
allows the site to cancel the <a>automated install prompt</a>, as
well as manually present the <a>site-triggered install prompt</a>.
</p>
<div class="note">
If the <a>BeforeInstallPromptEvent</a> is <em>not</em> cancelled, the
user agent is allowed to <a data-lt=
"presents an install prompt">present an automated install prompt</a>
to the end-user. Canceling the default action (via <a data-cite=
"DOM#dom-event-preventdefault">preventDefault</a>) prevents the user
agent from <a data-lt="presents an install prompt">presenting an
automated install prompt</a>. The user agent is free to run <a>steps
to notify that an install prompt is available</a> again at a later
time.
</div>
<p data-dfn-for="PromptResponseObject">
The <dfn>PromptResponseObject</dfn> contains the result of calling
<a data-lt="BeforeInstallPromptEvent.prompt()">prompt()</a>. It
contains one member, <dfn data-link-for=
"PromptResponseObject">userChoice</dfn>, which states the user's
chosen outcome.
</p>
<p>
An instance of a <a>BeforeInstallPromptEvent</a> has the following
internal slots:
</p>
<dl>
<dt>
<dfn>[[\didPrompt]]</dfn>
</dt>
<dd>
A boolean, initially <code>false</code>. Represents whether this
event was used to <a>present an install prompt</a> to the end-user.
</dd>
<dt>
<dfn>[[\userResponsePromise]]</dfn>
</dt>
<dd>
A promise that represents the outcome of <a>presenting an install
prompt</a>.
</dd>
</dl>
<section>
<h4>
<code>prompt()</code> method
</h4>
<p>
The <dfn>prompt</dfn> method, when called, runs the following
steps:
</p>
<ol>
<li>If <var>this</var>.<a>[[\userResponsePromise]]</a> is pending:
<ol>
<li>If this event's <a data-cite=
"!DOM#dom-event-istrusted"><code>isTrusted</code></a> attribute
is <code>false</code>, reject
<var>this</var>.<a>[[\userResponsePromise]]</a> with
<a>NotAllowedError</a>, optionally informing the developer that
untrusted events can't call <code>prompt()</code>.
</li>
<li>Else if <var>this</var>.<a>[[\didPrompt]]</a> is
<code>false</code>, set <var>this</var>.<a>[[\didPrompt]]</a>
to <code>true</code>, then <a>in parallel</a>, <a>request to
present an install prompt</a> with this event. Wait, possibly
indefinitely, for the end-user to make a choice.
</li>
</ol>
</li>
<li>Return <var>this</var>.<a>[[\userResponsePromise]]</a>.
</li>
</ol>
<p>
To <dfn>request to present an install prompt</dfn> with
<a>BeforeInstallPromptEvent</a> <var>event</var>:
</p>
<ol>
<li>
<a>Present an install prompt</a> and let <var>outcome</var> be
the result.
</li>
<li>Resolve <var>event</var>.<a>[[\userResponsePromise]]</a> with a
newly created <a>PromptResponseObject</a> whose <a data-link-for=
"PromptResponseObject">userChoice</a> member is the value of <var>
outcome</var>.
</li>
</ol>
</section>
<section class="informative">
<h4>
Usage example
</h4>
<p>
This example shows how one might prevent an automated install
prompt from showing until the user clicks a button to show a
<a>site-triggered install prompt</a>. In this way, the site can
leave installation at the user's discretion (rather than prompting
at an arbitrary time), whilst still providing a prominent UI to do
so.
</p>
<pre class="example" title=
"Using beforeinstallprompt to present an install button">
window.addEventListener("beforeinstallprompt", event => {
// Suppress automatic prompting.
event.preventDefault();
// Show the (disabled-by-default) install button. This button
// resolves the installButtonClicked promise when clicked.
installButton.disabled = false;
// Wait for the user to click the button.
installButton.addEventListener("click", async e => {
// The prompt() method can only be used once.
installButton.disabled = true;
// Show the prompt.
const { userChoice } = await event.prompt();
console.info(`user choice was: ${userChoice}`);
});
});
</pre>
</section>
</section>
<section>
<h3>
Extensions to the <code>Window</code> object
</h3>
<p>
The following extensions to the <dfn data-cite=
"!HTML#window"><code>Window</code></dfn> object specify the <a>event
handler attributes</a> on which events relating to the
<a>installation</a> of a web application are <a>fired</a>.
</p>
<pre class="idl">
partial interface Window {
attribute EventHandler onappinstalled;
attribute EventHandler onbeforeinstallprompt;
};
</pre>
<div class="example">
<p>
This example shows two ways of handling the "<a>appinstalled</a>"
event.
</p>
<pre class="example js">
function handleInstalled(ev) {
const date = new Date(ev.timeStamp / 1000);
console.log(`Yay! Our app got installed at ${date.toTimeString()}.`);
}
// Using the event handler IDL attribute
window.onappinstalled = handleInstalled;
// Using .addEventListener()
window.addEventListener("appinstalled", handleInstalled);
</pre>
</div>
<section data-dfn-for="Window">
<h4>
<code>onappinstalled</code> attribute
</h4>
<p>
The <dfn>onappinstalled</dfn> is an <a>event handler IDL
attribute</a> for the "<dfn>appinstalled</dfn>" event type. The
interface used for these events is the <a><code>Event</code>
interface</a> [[!DOM]]. This event is dispatched as a result of a
<a data-lt="installation succeeded">successful installation</a>
(see the <a>steps to install the web application</a>).
</p>
</section>
<section data-dfn-for="Window">
<h4>
<code>onbeforeinstallprompt</code> attribute
</h4>
<p>
The <dfn>onbeforeinstallprompt</dfn> is an <a>event handler IDL
attribute</a> for the "<dfn>beforeinstallprompt</dfn>" event type.
The interface used for these events is the
<a>BeforeInstallPromptEvent</a> interface (see the <a>steps to
notify that an install prompt is available</a>).
</p>
</section>
</section>
</section>
<section>
<h2>
Navigation scope
</h2>
<p data-link-for="WebAppManifest">
A <dfn>navigation scope</dfn> is a <a>URL</a> that represents the set
of URLs to which an <a>application context</a> can be navigated while
the manifest is <a>applied</a>. The <a>navigation scope</a> of a
manifest <var>manifest</var> is <var>manifest</var>["<a>scope</a>"].
</p>
<div class="note" data-link-for="WebAppManifest">
<p>
If the <a>scope</a> member is not present in the manifest, it
defaults to the parent path of the <a>start_url</a> member. For
example, if <a>start_url</a> is <code>/pages/welcome.html</code>, and
<a>scope</a> is missing, the navigation scope will be
<code>/pages/</code> on the same origin. If <a>start_url</a> is
<code>/pages/</code> (the trailing slash is important!), the
navigation scope will be <code>/pages/</code>.
</p>
<p>
Developers should take care, if they rely on the default behaviour,
that all of the application's page URLs begin with the parent path of
the start URL. To be safe, explicitly specify <a>scope</a>.
</p>
</div>
<p>
A <a>URL</a> <var>target</var> is said to be <dfn>within scope</dfn> of
<a>navigation scope</a> <var>scope</var> if the following algorithm
returns <code>true</code>:
</p>
<ol>
<li>Let <var>scopePath</var> be the elements of <var>scopes</var>'s
<a data-cite="!URL#concept-url-path">path</a>, separated by U+002F (/).
</li>
<li>Let <var>targetPath</var> be the elements of <var>target</var>'s
<a data-cite="!URL#concept-url-path">path</a>, separated by U+002F (/).
</li>
<li>If <var>target</var> is <a>same origin</a> as <var>scope</var> and
<var>targetPath</var> starts with <var>scopePath</var>, return
<code>true</code>.
</li>
<li>Otherwise, return <code>false</code>.
</li>
</ol>
<div class="note" title="Scope is a simple string match">
The URL string matching in this algorithm is prefix-based rather than
path-structural (e.g. a target URL string
<code>/prefix-of/resource.html</code> will match an app with scope
<code>/prefix</code>, even though the path segment name is not an exact
match). This is intentional for consistency with <a data-cite=
"!SERVICE-WORKERS-1#scope-match-algorithm">Service Workers</a>. To
avoid unexpected behavior, use a scope ending in a <code>/</code>.
</div>
<div class="issue" title="🐒 patch">
<p>
Enforcing the navigation scope depends on [[!HTML]]'s navigate
algorithm. As such, the following algorithm monkey patches [[!HTML]].
<a href="https://www.w3.org/Bugs/Public/show_bug.cgi?id=27653">Bug
27653</a> has been filed to address this.
</p>
</div>
<p>
The user agent MUST navigate the application context as per [[!HTML]]'s
<a>navigate algorithm</a> with exceptions enabled. If the URL of the
resource being loaded in the navigation is not <a>within scope</a> of
the navigation scope of the application context's manifest, then the
user agent MUST behave as if the application context is not <a>allowed
to navigate</a>. This provides the ability for the user agent to
perform the navigation in a different browsing context, or in a
different user agent entirely. If during the handle redirects step of
HTML's <a>navigate algorithm</a> the redirect URL is not <a>within
scope</a> of the navigation scope of the application context's
manifest, abort HTML's navigation algorithm with a
<code>SecurityError</code>.
</p>
<section data-link-for="DisplayModeType">
<h3 id="navigation-scope-security-considerations">
Security considerations
</h3>
<p>
It should not be possible to navigate the <a>top-level browsing
context</a> to somewhere outside the scope while the <a>manifest</a>
is <a>applied</a> to the <a>top-level browsing context</a>. That's
not to say that the web application cannot be navigated: just that
the set of URLs to which the manifest applies is restricted by the
<a>navigation scope</a>.
</p>
</section>
<section>
<h3>
Deep links
</h3>
<div class="issue" data-number="363"></div>
<p>
A <dfn>deep link</dfn> is a URL that is <a>within scope</a> of the
navigation scope of an <a>installed</a> web application's manifest.
</p>
<p>
An <a>application context</a> can be instantiated through a <a>deep
link</a>, in which case, the manifest is applied and the <a>deep
link</a> is loaded within the context of a web application.
</p>
<div class="note">
<p>
The concept of a <a>deep link</a> is useful in that it allows
hyperlinking from one installed application to another. This can be
from a native application to an <a>installed</a> web application
(and possibly vice versa!). Theoretically, this can provide
seamless context switching between native and web applications
through standard hyperlinks. And in the case where a particular web
application is not <a>installed</a>, the OS can just open the link
in the user's preferred web browser.
</p>
<p>
Implementers are encouraged make such context switching obvious to
the user, for example, by adhering to the human interface
guidelines of the underlying platform with respect to application
switching.
</p>
</div>
</section>
</section>
<section data-dfn-for="DisplayModeType" data-link-for="DisplayModeType">
<h2>
Display modes
</h2>
<p>
A <dfn>display mode</dfn> represents how the web application is being
presented within the context of an OS (e.g., in fullscreen, etc.).
Display modes correspond to user interface (UI) metaphors and
functionality in use on a given platform. The UI conventions of the
display modes are purely advisory and implementers are free to
interpret them how they best see fit.
</p>
<p>
Once a user agent applies a particular <a>display mode</a> to an
<a>application context</a>, it becomes the <dfn>default display
mode</dfn> for the <a>top-level browsing context</a> (i.e., it is used
as the display mode when the window is <a>navigated</a>). The user
agent MAY override the <a>default display mode</a> for security reasons
(e.g., the <a>top-level browsing context</a> is <a>navigated</a> to
another origin) and/or the user agent MAY provide the user with a means
of switching to another <a>display mode</a>.
</p>
<p>
When the <a data-link-for="WebAppManifest">display</a> member is
missing, or if there is no valid <a data-link-for=
"WebAppManifest">display</a> member, the user agent uses the
<a>browser</a> <a>display mode</a> as the <a>default display mode</a>.
As such, the user agent is REQUIRED to support the <a>browser</a>
<a>display mode</a>.
</p>
<p>
Each <a>display mode</a>, except <code>browser</code>, has a
<dfn data-lt="fallback display modes">fallback display mode</dfn>,
which is the <a>display mode</a> that the user agent can try to use if
it doesn't support a particular <a>display mode</a>. If the user agent
does support a <a>fallback display mode</a>, then it checks to see if
it can use that <a>display mode</a>'s <a>fallback display mode</a>.
This creates a fallback chain, with the <a>default display mode</a>
(<code>browser</code>) being the last item in the chain.
</p>
<div class="example">
<p>
For example, SuperSecure Browser (a fictitious browser) only supports
the <code>minimal-ui</code> and <code>browser</code> display modes,
but a developer declares that she wants <code>fullscreen</code> in
the manifest. In this case, the user agent will first check if it
supports <code>fullscreen</code> (it doesn't), so it falls back to
<code>standalone</code> (which it also doesn't support), and
ultimately falls back to <code>minimal-ui</code>.
</p>
</div>
<p>
The <dfn>display modes values</dfn> defined by
<dfn>DisplayModeType</dfn>, and their corresponding <a>fallback display
modes</a> are as follows:
</p>
<dl>
<dt>
<dfn>fullscreen</dfn>
</dt>
<dd>
Opens the web application without any user agent chrome and takes up
the entirety of the available display area.
</dd>
<dd>
The <a>fallback display mode</a> for <code>fullscreen</code> is
<code>standalone</code>.
</dd>
<dt>
<dfn>standalone</dfn>
</dt>
<dd>
Opens the web application to look and feel like a standalone native
application. This can include the application having a different
window, its own icon in the application launcher, etc. In this mode,
the user agent will exclude standard browser UI elements such as an
URL bar, but can include other system UI elements such as a status
bar and/or system back button.
</dd>
<dd>
The <a>fallback display mode</a> for <code>standalone</code> is
<code>minimal-ui</code>.
</dd>
<dt>
<dfn>minimal-ui</dfn>
</dt>
<dd>
This mode is similar to <a>standalone</a>, but provides the end-user
with some means to access a minimal set of UI elements for
controlling navigation (i.e., back, forward, reload, and perhaps some
way of viewing the document's address). A user agent can include
other platform specific UI elements, such as "share" and "print"
buttons or whatever is customary on the platform and user agent.
</dd>
<dd>
The <a>fallback display mode</a> for <code>minimal-ui</code> is
<code>browser</code>.
</dd>
<dt>
<dfn>browser</dfn>
</dt>
<dd>
Opens the web application using the platform-specific convention for
opening hyperlinks in the user agent (e.g., in a browser tab or a new
window).
</dd>
<dd>
The <code>browser</code> <a>display mode</a> doesn't have a
<a>fallback display mode</a> (conforming user agents are required to
support the <code>browser</code> <a>display mode</a>).
</dd>
</dl>
<p class="note">
The <a>fullscreen</a> <a>display mode</a> is orthogonal to, and works
independently of, the [[WHATWG-FULLSCREEN]] API. The <a>fullscreen</a>
<a>display mode</a> affects the fullscreen state of the browser window,
while the [[WHATWG-FULLSCREEN]] API operates on an element contained
within the viewport. As such, a web application can have its <a>display