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HTML is a form of markup that is oriented toward the presentation
of single-page text documents with specialized rendering software
called an HTML user agent, the most common example of which
is a web browser. HTML provides a means by which the document's
main content can be annotated with various kinds of metadata and
rendering hints. The rendering cues may range from minor text
decorations, such as specifying that a certain word be underlined
or that an image be inserted, to sophisticated scripts, imagemaps,
and form definitions that control web browsers. The metadata may
include information about the document's title and author, structural
information such as an expression of how the content is segmented
into paragraphs, lists, headings, arbitrary divisions, etc., and
most importantly, information that allows the document to be linked
to other documents. Although most HTML documents contain a main
body of text, it is not uncommon to encounter minimal HTML documents
that exist only to present visual media in a web browser.
HTML is usually authored in a text editor and stored in
a text file with a name usually ending in ".html"
or ".htm". Such a file is typically created with
the intent that it will be accessed over the World Wide Web, which
uses the HTTP network protocol to transfer the files to
requesting computers. A request for an HTML document is
usually made by a web browser, such as Apple Safari, Mozilla
Firefox, or Microsoft Internet Explorer, and upon receipt,
the document is rendered and presented to the user. However, HTML
can also be transmitted in email messages and rendered by
software for email reading, or processed by cellphones that have
web browsing capabilities.
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