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In order to allow external applications to track what's happening inside the browser, Mozilla implements an MSAA (Microsoft Active Accessibility) server. This lets outside programs—such as screen readers, voice recognition software, and other accessibility-enhancing applications—track focus changes, listen for events, and read window contents.

IEnumVARIANT is part of the API that allows applications to retrieve a number of accessible objects from the MSAA server at once. It generally improves the performance of communication with external applications.

This preference exists largely for debugging purposes.

Possible values and their effects


MSAA calls to IEnumVARIANT will fail, forcing calls to get_accChild() or accNavigate() instead.


Return VARIANT objects for valid IEnumVARIANT calls to the MSAA server. (Default)

First checked in

2002-10-24 by Aaron Leventhal

Has an effect in

  • Netscape (all versions since 7.1)
  • Mozilla Suite (all versions since 1.2)
  • Mozilla Phoenix (all versions since 0.4)
  • Mozilla Firebird (all versions)
  • Mozilla Firefox (all versions)
  • SeaMonkey (all versions)

Related preferences

Related bugs

External links