Web App Manifest link rel Lookup
Checks a parsed link for the manifest relation and a nonempty href. This local check does not fetch or validate the manifest document.
Description
A web app manifest link associates a document with application metadata.
A web app manifest link associates a document with application metadata. Identifying its relation and a supplied destination is a local prerequisite to fetching and validating that metadata.1
The tool returns manifestRelation, nonemptyHref, passes. The fields describe the supplied local pattern or effective state, or contain the formatted markup shown below.
When to use Web App Manifest link rel Lookup
Use this for the following task: Checks a parsed link for the manifest relation and a nonempty href. This local check does not fetch or validate the manifest document. Provide the requested local fields extracted from the relevant element or attribute.
How to use Web App Manifest link rel Lookup and understand its results
- Prepare the parsed element names, attribute values or direct element-child lists requested below. Keep attribute presence separate from its value.
- Enter rel, href according to the field table, then run the tool.
- Read manifestRelation, nonemptyHref, passes. Check the effective state, recognized-token flags or generated markup against the rules below.
- Correct any reported local mismatch and check the resulting markup in its intended document and browser context.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| rel | Rel | string; maximum text length 100000 | Required |
| href | Href | string; maximum text length 100000 | Required |
Supply rel and href. Fold case on whitespace-separated relation tokens and independently test whether href contains non-whitespace content.
passes = rel contains manifest AND href has an HTML-whitespace token The symbols and boundary conditions refer to the supplied fields and the implementation described above.
| Output field | Meaning | Value type |
|---|---|---|
| manifestRelation | Manifest Relation | boolean |
| nonemptyHref | Nonempty Href | boolean |
| passes | Passes | boolean |
{
"input": {
"rel": "MANIFEST",
"href": "/app.webmanifest"
},
"output": {
"manifestRelation": true,
"nonemptyHref": true,
"passes": true
}
}Limitations and assumptions
Relative href values are accepted. URL syntax, fetch success, manifest JSON and installability are not validated.
The tool does not fetch a page, run a browser or validate an entire HTML document. Malformed tool requests produce input errors; valid requests can still report unrecognized values or failed local checks.
Alternative or Complementary methods
Choose link preload as= Types List when you need its operation: Checks the six current HTML preload as destinations and translates fetch to the empty Fetch destination. Modulepreload has a separate vocabulary and is outside this lookup. Choose Canonical link rel Check for the complementary operation: Checks the canonical relation and a nonempty parsed href. Relative href values are accepted; this does not establish URL validity or canonical selection by search engines.
Background reference: HTML Standard: Web App Manifest link rel Lookup.
References
Similar or alternative tools
- link preload as= Types List
Checks the six current HTML preload as destinations and translates fetch to the empty Fetch destination. Modulepreload has a separate vocabulary and is outside this lookup.
- Canonical link rel Check
Checks the canonical relation and a nonempty parsed href. Relative href values are accepted; this does not establish URL validity or canonical selection by search engines.