In kde4 its possible to define desktop wide mouse gestures.
Here is a file to include in systemsettings to get mousegestures in chrome and most other browsers.
(This is a modified version of the script without firefox support cause in firefox i use a extra extension for mousegestures. There are also some more gestures then in the original script)
The original Skript can be found here: Link There is also a more detailed description, what browsers are supported.