資料來源 : WordNet®
uniform resource locator
n : the address of a web page on the world wide web [syn: {URL},
{universal resource locator}]
資料來源 : Free On-Line Dictionary of Computing
Uniform Resource Locator
(URL, previously "Universal") A {standard}
way of specifying the location of an object, typically a {web
page}, on the {Internet}. Other types of object are described
below. URLs are the form of address used on the {World-Wide
Web}. They are used in {HTML} documents to specify the target
of a {hyperlink} which is often another HTML document
(possibly stored on another computer).
Here are some example URLs:
http://www.w3.org/default.html
http://www.acme.co.uk:8080/images/map.gif
http://www.foldoc.org/?Uniform+Resource+Locator
http://www.w3.org/default.html#Introduction
ftp://wuarchive.wustl.edu/mirrors/msdos/graphics/gifkit.zip
ftp://spy:[email protected]/pub/topsecret/weapon.tgz
mailto:[email protected]
news:alt.hypertext
telnet://dra.com
The part before the first colon specifies the access scheme or
{protocol}. Commonly implemented schemes include: {ftp},
{http} (World-Wide Web), {gopher} or {WAIS}. The "file"
scheme should only be used to refer to a file on the same
host. Other less commonly used schemes include {news},
{telnet} or mailto ({e-mail}).
The part after the colon is interpreted according to the
access scheme. In general, two slashes after the colon
introduce a {hostname} (host:port is also valid, or for {FTP}
user:passwd@host or user@host). The {port} number is usually
omitted and defaults to the standard port for the scheme,
e.g. port 80 for HTTP.
For an HTTP or FTP URL the next part is a {pathname} which is
usually related to the pathname of a file on the server. The
file can contain any type of data but only certain types are
interpreted directly by most {browsers}. These include {HTML}
and images in {gif} or {jpeg} format. The file's type is
given by a {MIME} type in the HTTP headers returned by the
server, e.g. "text/html", "image/gif", and is usually also
indicated by its {filename extension}. A file whose type is
not recognised directly by the browser may be passed to an
external "viewer" {application}, e.g. a sound player.
The last (optional) part of the URL may be a query string
preceded by "?" or a "fragment identifier" preceded by "#".
The later indicates a particular position within the specified
document.
Only alphanumerics, reserved characters (:/?#"<>%+) used for
their reserved purposes and "$", "-", "_", ".", "&", "+" are
safe and may be transmitted unencoded. Other characters are
encoded as a "%" followed by two {hexadecimal} digits. Space
may also be encoded as "+". Standard {SGML} "&;"
character entity encodings (e.g. "é") are also accepted
when URLs are embedded in HTML. The terminating semicolon may
be omitted if & is followed by a non-letter character.
{The authoritative W3C URL specification
(http://www.w3.org/hypertext/WWW/Addressing/Addressing.html)}.
(2000-02-17)