Licensing: this page is under CC0, not the MIT License.
about: URLs serve as identifier, potentially with an associated resource. The identifier is given in the URL's scheme data.
|"blank"||A resource whose Content-Type is text/html;charset=utf-8 and entity body is the empty string.|
|"invalid"||-||Used to represent a network error. See also CSS Values and Units.|
|"legacy-compat"||-||Used in HTML for XSLT serializers.|
|"srcdoc"||-||Used in HTML for its <iframe srcdoc> feature.|
|"unicorn"||A resource whose Content-Type is image/svg+xml and entity body is the contents of unicorn.svg.||Unicorn!|
To obtain a resource from an about: URL, run these steps:
- If URL's scheme data is not the literal string "blank" or "unicorn", return a network error. (URL's query and URL's fragment are simply not taken into account and can be anything.)
- Return the resource corresponding to the identifier as listed in the table above, with HTTP status code 200 and HTTP status text "OK".
|about:blanK||network error (uppercase K)|
|about:bl%61nk||network error (no percent decoding by either the URL parser or the obtain a resource algorithm)|
|about:blank?teehee||works (query does not matter)|
|about:blank?teehee#hihi||works (fragment does not matter either)|
- Let input be the concatenation of URL's scheme data, followed by "?" and URL's query if URL's query is non-null, followed by "#" and URL's fragment if URL's fragment is non-null.
- Set input to the result of percent decoding input.
- If input starts with a U+FEFF, remove a single occurrence from the start of input.
- Return input.
See Bug 19494 and other stuff linked from there.
To obtain a resource from a parsed URL whose scheme is a ASCII case-insensitive match for "data:", run these steps:
- Set input to the URL’s scheme data.
- If the URL’s query is not null, append "?" and the query to input.
- If input does not contain a U+002C COMMA code point, return a network error. (Note: the comma can come either from the scheme data or the query.)
- Split input at the first comma. Set header and body to the parts before and after the comma, respectively. (Issue: what if the comma is an a MIME quoted string for a parameter value? Example:
- Set body-bytes to the result of running percent decode to bytes on body.
- If header ends with ";base64" (Issue: Match how strictly? Case sensitive or not? Allow whitespace? Percent-encoding?) then:
- Remove the matched substring from header
- Decode body-bytes with the Base 64 Encoding. (Issues: Also accept the URL and Filename Safe Alphabet? Mixed alphabets in the same body? Ignore which non-alphabet bytes? Missing/too little/too much padding?)
- Return a response with header as a Content-Type header and body-bytes as the body. The parsing and interpretation of header must be the same as for an HTTP Content-Type header.
To percent decode to bytes, run the same algorithm as percent decode but replacing the last step with "Return bytes."