From MozillaZine Knowledge Base



HTTP is the application-layer protocol with which most web pages are transferred. As part of the connection between client and server in HTTP 1.1, the client lists in what way it can/prefers to accept information (content negotiation). This preference controls which MIME types the application will report it supports.

Possible values and their effects

A comma-seperated list of MIME types with optional "q" (quality) values. A quality value says that the application prefers one type over another, but supports both. Quality values can be from 0 (not supported) to 1 (preferred format). If a quality value is omitted, it defaults to 1.

Minimo default:


All others default:


Default in trunk builds after 2007-03-08:


First checked in

2001-05-16 by Simon Fraser

Has an effect in

  • Netscape (all versions since 6.1)
  • Mozilla Suite (all versions since 0.9.1)
  • Phoenix (all versions)
  • Firebird (all versions)
  • Firefox (all versions)
  • Thunderbird (all versions)
  • Minimo (all versions)
  • SeaMonkey (all versions)

Related bugs

Related preferences

External links