script-content

Validate the body of <script> elements against the spec that governs the value of its type attribute.

Currently supported content formats:

type value	Spec
importmap	HTML Living Standard § Parse an import map string
speculationrules	HTML Living Standard § 7.6 Speculation rules

type attribute matching is ASCII case-insensitive, matching how user agents look up the script's effective MIME type.

type="importmap"

The rule reports the following issues for inline import maps:

• The element body is empty or whitespace-only
• The body cannot be parsed as JSON
• The top-level value is not a JSON object
• The top-level value contains a key other than imports, scopes, or integrity
• imports or scopes is not a JSON object
• A specifier map (imports, or a value inside scopes) contains an empty key
• A specifier map address (the value side) is not a string
• A specifier map address is not a URL-like specifier (does not start with /, ./, ../, and is not an absolute URL)
• A specifier key ends with / but its address does not
• integrity is not a JSON object
• An integrity key is not a URL-like specifier
• An integrity value is not a string

❌ Examples of incorrect code for this rule

<script type="importmap"></script>
<script type="importmap">
  {
    "forbidden": {}
  }
</script>
<script type="importmap">
  {
    "imports": {
      "dir/": "/path/to/dir"
    }
  }
</script>

✅ Examples of correct code for this rule

<script type="importmap">
  {
    "imports": {
      "app": "/path/to/app.js",
      "dir/": "/path/to/dir/"
    },
    "scopes": {
      "/scope/": {
        "x": "./y.js"
      }
    }
  }
</script>

type="speculationrules"

Speculation Rules are defined in the HTML Living Standard § 7.6 (the feature originated as the WICG nav-speculation draft, which now redirects to the HTML Standard). The rule reports the following issues for inline speculation rules:

• The element body is empty, whitespace-only, or cannot be parsed as JSON
• The top-level value is not a JSON object, or has no prefetch or prerender property
• A top-level key other than tag, prefetch, or prerender is present
• A prefetch / prerender value is not a JSON array, or a rule in it is not a JSON object
• A rule has a key other than source, urls, where, relative_to, eagerness, referrer_policy, tag, requires, expects_no_vary_search, or target_hint
• source is not a string, or is a value other than list or document
• A list rule (explicit or inferred from urls) is missing urls, or has a where
• A document rule (explicit or inferred from where) is missing where, or has urls
• A rule has no source and its source cannot be inferred (it has neither urls nor where, or has both)
• urls is not a JSON array, is empty, or contains a non-string or empty-string item
• eagerness is not a string, or is a value other than immediate, eager, moderate, or conservative
• where is not a JSON object, or does not contain exactly one predicate (and, or, not, href_matches, or selector_matches)
• An and / or predicate is not a JSON array, or is empty
• An href_matches / selector_matches pattern is not a string or an array of strings, is empty, or contains an empty-string item

❌ Examples of incorrect code for this rule

<script type="speculationrules">
  {
    "prefetch": [{ "source": "list" }]
  }
</script>
<script type="speculationrules">
  {
    "prefetch": [{ "source": "document", "where": {} }]
  }
</script>

✅ Examples of correct code for this rule

<script type="speculationrules">
  {
    "prefetch": [
      {
        "source": "document",
        "where": {
          "and": [{ "href_matches": "/*" }, { "not": { "selector_matches": ".no-prefetch" } }]
        },
        "eagerness": "moderate"
      }
    ],
    "prerender": [{ "source": "list", "urls": ["/next"] }]
  }
</script>

Interface

{
  "script-content": boolean
}

Validate the body of <script> elements when the type attribute selects a content format that has a spec (currently: importmap, speculationrules).

Default Severity

error