We're looking for a user researcher to understand the needs of developers and designers. Is this you or someone you know? Check out the post: https://mzl.la/2IGzdXS


This interface exposes the general notion of a scheduled object with an integral priority value. Following UNIX conventions, smaller (and possibly negative) values have higher priority.
Gecko 1.8
Inherits from: nsISupports Last changed in Gecko 1.8 (Firefox 1.5 / Thunderbird 1.5 / SeaMonkey 1.0)

This interface does not strictly define what happens when the priority of an object is changed. An implementation of this interface is free to define the side-effects of changing the priority of an object. In some cases, changing the priority of an object may be disallowed (resulting in an exception being thrown) or may simply be ignored.

Method overview

void adjustPriority(in long delta);


Attribute Type Description
priority long The object's priority. It can be modified to change the priority of the object. Typical priority values are defined in the idl file as PRIORITY_HIGHEST ... PRIORITY_LOWEST. The implementation is free to truncate a given priority value to whatever limits are appropriate. Typically this attribute is initialized to PRIORITY_NORMAL, but implementations may choose to assign a different initial value.


Constant Value Description
PRIORITY_HIGHEST -20 The highest priority.
PRIORITY_HIGH -10 Higher than normal priority.
PRIORITY_NORMAL 0 The default priority.
PRIORITY_LOW 10 Lower than normal priority.
PRIORITY_LOWEST 20 The lowest priority.



This method adjusts the priority attribute by a given amount (delta).

void adjustPriority(
  in long delta
The amount by which to adjust the priority attribute.

See also

Document Tags and Contributors

Contributors to this page: Sheppy, trevorh, Nickolay, LouCypher, Ted_Mielczarek
Last updated by: Sheppy,