Internet media type

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An Internet media type,[1] originally called a MIME type after MIME and sometimes a Content-type after the name of a header in several protocols whose value is such a type, is a two-part identifier for file formats on the Internet. The identifiers were originally defined in RFC 2046 for use in e-mail sent through SMTP, but their use has expanded to other protocols such as HTTP and SIP.

A media type is composed of at least two parts: a type, a subtype, and one or more optional parameters. For example, subtypes of text type has an additional charset parameter that can be included to indicate the character encoding, and subtypes of multipart type often define a boundary between parts.

Types that begin with "x-" are nonstandard -- they not registered with IANA.[2] Subtypes that begin with vnd. are vendor-specific.[3]

[edit] List of common media types

IANA manages a registry of media types and character encodings. The organization makes a list available to the public through the Web. Some of the more notable media types used on the Web are listed below:

  • Type audio: Audio
  • Type example
  • Type image
  • Type message
  • Type model: 3D models
  • Type multipart: Archives and other objects made of more than one part
    • multipart/mixed or multipart/alternative: MIME e-mail
  • Type text: Human-readable text and source code
    • text/css: Cascading Style Sheets
    • text/html; charset=UTF-8: HTML in the UTF-8 character encoding
    • text/javascript: Depreciated. RFC 4329 replaces this type with application/javascript.
    • text/plain; charset=ISO 8859-1: Textual data in ISO 8859-1 character encoding
    • text/plain; charset=UTF-8: Textual data in the UTF-8 character encoding
  • Type video: Video
  • Type application: Multipurpose files
    • application/javascript: ECMAScript (such as JavaScript)
    • application/octet-stream: arbitrary byte streams otherwise unspecified. This is thought of as the "default" media type used by several operating systems, often used to identify executable files, files of unknown type, or files that should be downloaded in protocols that do not provide a separate "content disposition" header. RFC 2046 specifies this as the fallback for unrecognized subtypes of other types.
    • application/ogg: Ogg, a multimedia bitstream container format
    • application/postscript: PostScript program, often used to define a page to be printed.
    • application/xhtml+xml; charset=UTF-8: XHTML, a successor to HTML, in UTF-8 encoding

[edit] References

  1. ^ Internet Media Type registration, consistency of use. W3C (2002-06-03). Retrieved on 2006-11-29.
  2. ^ Freed, N. (November 1996). RFC 2045 - Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies 15 (section 6.3). IETF. Retrieved on 2006-11-29.
  3. ^ Freed, N.; Klensin, J., Postel, J. (November 1996). RFC 2048 - Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures 3-4 (section 2.1.2). IETF. Retrieved on 2006-11-29.
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