All references are normative unless marked "Non-normative".
As of today the Web community lacks a sufficiently complete, reliable, interoperable, and tested specification for the manner in which content sniffing takes place on the Web. We encourage implementers to exercise caution in this area as the Web community makes progress towards addressing this issue.
Media Type Sniffing (URL: http://tools.ietf.org/html/draft-ietf-websec-mime-sniff-03), A. Barth, I. Hickson. IETF.
Note: URLs can be used in numerous different manners, in many differing contexts. For the purpose of producing strict URLs one may wish to consider [RFC3986] (URL: #refsRFC3986)[RFC3987] (URL: #refsRFC3987)https://url.spec.whatwg.org/ (URL: https://url.spec.whatwg.org/)
Most of the URL-related terms used in the HTML specification (URL, absolute
URL (URL: #absolute-url), relative URL (URL: #relative-url), relative schemes,
scheme component, scheme data,
username, password, host,
port, path, query,
fragment, percent encode (URL: #percent-encode), get the base,
and UTF-8 percent encode (URL: #utf-8-percent-encode)) can be straightforwardly mapped to the
terminology of [RFC3986] (URL: #refsRFC3986)[RFC3987] (URL: #refsRFC3987)
URLUtils (URL: #urlutils) (formerly known as
URL) collection of attributes
protocol) and its required definitions
(input (URL: #the-input-element), query encoding, url,
update steps, set the input) are considered common
practice nowadays. Some of the URL-related terms are still being refined (e.g. URL
parser (URL: #url-parser-0), parse errors, URL serializer,
default encode set (URL: #default-encode-set), and percent decode (URL: #percent-decode)).
As a word of caution, there are notable differences in the manner in which Web browsers and other software stacks outside the HTML context handle URLs. While no changes would be accepted to URL processing that would break existing Web content, some important parts of URL processing should therefore be considered as implementation-defined (e.g. parsing file: URLs or operating on URLs that would be syntax errors under the [RFC3986] (URL: #refsRFC3986)[RFC3987] (URL: #refsRFC3987)
URL (URL: http://www.w3.org/TR/url/), E. Arvidsson, M.[tm] Smith. W3C.