This translation is incomplete. Please help translate this article from English
The Geometry.jsm JavaScript code module provides routines for performing common geometry operations on points and rectangles. It exports two classes: Point and Rect.
To use these routines, you first need to import the code module into your JavaScript scope:
Components.utils.import("resource://gre/modules/Geometry.jsm");
Once you've imported the module, you can then use the Point and Rect classes.
Note: Although this module is usable from mobile, and is present in Firefox 4, it's currently not used in Firefox 4 and attempting to use it may produce unreliable results there.