The manifest attribute on <html> was used to point to a cache manifest file (typically *.appcache) for the HTML5 Application Cache (AppCache) API. It let developers list HTML, CSS, JavaScript, and images to cache for offline use. Application Cache is deprecated and removed from all modern browsers. Do not use this attribute in new projects—use Service Workers and the Cache API instead. Also do not confuse it with <link rel="manifest">, which is a separate, modern PWA feature.
Root element attribute.
Legacy offline API.
Not in modern browsers.
Different feature.
CACHE, NETWORK, FALLBACK.
Modern replacement.
manifest AttributeThe original purpose of the manifest attribute was to link an HTML document to a cache manifest file. That text file listed resources the browser should store locally so the web app could load when the user was offline or on a slow connection. When the browser saw <html manifest="example.appcache">, it fetched the manifest, cached the listed files, and served them from cache on subsequent visits.
Application Cache had significant design flaws (difficult updates, unpredictable caching behavior) and was superseded by Service Workers. The HTML specification removed the manifest attribute, and browsers dropped AppCache support entirely. You may still encounter it in legacy tutorials or old codebases, which is why it belongs in an attributes reference.
<link rel="manifest">The deprecated manifest attribute on <html> pointed to an .appcache file for offline caching. The modern <link rel="manifest" href="manifest.json"> in <head> links to a JSON Web App Manifest for PWA icons, name, and install behavior—it does not replace Application Cache. Offline caching today requires a Service Worker script.
Legacy syntax on the root element (shown for recognition only—do not use in new projects):
<!DOCTYPE html>
<html manifest="example.appcache">
<head>
<title>Offline Web App</title>
</head>
<body>
<p>This page linked to a cache manifest.</p>
</body>
</html>Sample cache manifest file (example.appcache):
CACHE MANIFEST
# Version 1 — resources to cache offline
index.html
styles.css
app.js
logo.png
NETWORK:
*
FALLBACK:
/offline.htmlModern equivalent for offline + installable apps:
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="manifest" href="/manifest.json">
</head>
<body>…</body>
<script>
// Register a Service Worker for offline caching
navigator.serviceWorker.register("/sw.js");
</script>
</html><html> element.*.appcache or *.manifest.CACHE MANIFEST.CACHE: (listed files), optional NETWORK: and FALLBACK:.<link rel="manifest">.The manifest attribute accepted a single URL string pointing to the cache manifest file:
manifest="example.appcache" — Relative path to a cache manifest in the same directory.manifest="/cache/app.manifest" — Absolute path from the site root.manifest="https://cdn.example.com/v2.appcache" — Full URL (same-origin rules applied in practice).CACHE MANIFEST (required header) — First line of every manifest file.CACHE: (implicit) — URLs listed after the header are cached for offline use.NETWORK: — URLs that must always be fetched from the network (e.g. * for all).FALLBACK: — Map of online URL to offline fallback page (e.g. / /offline.html).// Legacy dynamic pattern — AppCache no longer runs
document.documentElement.setAttribute("manifest", "dynamic.appcache");| Use Case | Legacy (avoid) | Modern replacement |
|---|---|---|
| Offline HTML/CSS/JS cache | <html manifest="app.appcache"> | Service Worker + Cache API |
| Cache manifest file | *.appcache text file | sw.js with caches.open() |
| PWA app name & icons | N/A (not AppCache) | <link rel="manifest" href="manifest.json"> |
| Network-only URLs | NETWORK: * in .appcache | Service Worker fetch handler |
| Offline fallback page | FALLBACK: / /offline.html | Service Worker respondWith |
| Dynamic manifest URL | setAttribute("manifest", url) | Update Service Worker registration |
| Element | Supported? | Notes |
|---|---|---|
<html> | Obsolete | Only element that ever supported manifest |
<head> / <link rel="manifest"> | Modern (different) | Web App Manifest JSON—not the html manifest attribute |
<body>, <div>, etc. | No | manifest was never valid on other elements |
<script> | No | Service Workers are registered via JS, not a script attribute |
manifest on <html> vs <link rel="manifest">| Feature | manifest on <html> | <link rel="manifest"> |
|---|---|---|
| Status | Deprecated & removed | Active W3C standard |
| File type | Text cache manifest (.appcache) | JSON Web App Manifest |
| Primary purpose | Offline resource caching (AppCache) | PWA name, icons, theme, display mode |
| Location | Attribute on <html> | <link> in <head> |
| Offline caching | Handled AppCache (removed) | Does not cache files—use Service Worker |
| Browser support today | None | All modern browsers |
Legacy AppCache markup, modern PWA replacement, and dynamic setAttribute (obsolete pattern).
Structure of a legacy cache manifest file (AppCache no longer runs in browsers):
CACHE MANIFEST index.html styles.css app.js NETWORK: * FALLBACK: / /offline.html
Linked from <html manifest="example.appcache">. Listed under CACHE were stored offline; NETWORK: and FALLBACK: controlled other requests.
Historical pattern linking an HTML page to a cache manifest:
<!DOCTYPE html>
<html manifest="example.appcache">
<head>
<title>Offline Web App</title>
</head>
<body>
<p>This is an example of an offline web application.</p>
</body>
</html>When supported, the browser parsed the manifest URL, downloaded listed files into the application cache, and served them on repeat visits even offline. Updates required changing the manifest file and often confused developers—a key reason Service Workers replaced AppCache.
Today, link a JSON manifest for install metadata and register a Service Worker for offline caching:
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="manifest" href="/manifest.json">
</head>
<body>…</body>
<script>
if ("serviceWorker" in navigator) {
navigator.serviceWorker.register("/sw.js");
}
</script>
</html>The Web App Manifest JSON tells the browser how to install and display the app. The Service Worker intercepts network requests and serves cached responses when offline. These are separate standards from the removed html manifest attribute.
Legacy pattern for changing the manifest URL at runtime (no longer effective):
<script>
document.documentElement.setAttribute("manifest", "dynamic.appcache");
</script>Developers could point different users or conditions to different cache manifests. Because AppCache is gone, the attribute change has no caching effect. Update Service Worker logic instead for dynamic offline behavior.
aria-live regions when the app detects loss of connectivity—do not rely on silent cache failures.rel="manifest" install flows should be optional and not block core page access.FALLBACK: pages and modern offline pages need proper headings, contrast, and focus management.Points to .appcache file.
Parses CACHE, NETWORK, FALLBACK.
AppCache served offline visits.
Replaced by Service Workers today.
Application Cache and the manifest attribute on <html> are removed from all modern browsers. Chrome dropped AppCache in 2020; Firefox, Safari, and Edge followed. The attribute remains in specs only for historical reference.
Use Service Workers for offline caching and <link rel="manifest"> for PWA metadata.
Bottom line: Never use html manifest in new code. Adopt Service Workers and the Web App Manifest (rel="manifest") instead.
<link rel="manifest" href="manifest.json"> for PWA metadatamanifest attributes when migrating old appsmanifest to <html> in new projectsmanifest with rel="manifest"*.appcache files for offline supportsetAttribute("manifest", …) enables cachingThe manifest attribute on <html> was a powerful idea for offline web applications—linking pages to cache manifest files through Application Cache. However, AppCache proved difficult to maintain and was removed from browsers and the HTML living standard.
For new projects, use Service Workers for offline caching and <link rel="manifest"> for installable PWA metadata. Understanding the legacy manifest attribute helps you read old code and migrate confidently to modern offline patterns.
manifestBookmark these before working with offline web apps.
Root element attribute.
Scope0% browser support.
Status.appcache vs JSON.
CompareModern offline cache.
ReplaceCACHE, NETWORK, FALLBACK.
Format<html> element to a cache manifest file (.appcache) for the Application Cache API, listing resources to store for offline use. Browsers no longer support Application Cache.manifest attribute linked to a text AppCache file (removed). <link rel="manifest"> links to JSON for PWA install metadata—a different, active standard. Offline caching requires Service Workers.<html> element ever supported it. The attribute is obsolete and should not appear in new markup.CACHE MANIFEST, then lists URLs to cache. Optional NETWORK: and FALLBACK: sections control online-only resources and offline fallback pages.navigator.serviceWorker.register("/sw.js") and use the Cache API inside the worker. Add <link rel="manifest" href="manifest.json"> if you want installable PWA features.Explore the deprecated manifest attribute, .appcache file format, and Service Worker replacements in the Try It editor.
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