Firefox supports multi gesture on mac OSX

1.
   Key-in about:config on your Firefox URL field.
   And key-in gesture on search field.
2.
   edit

   Tree fingers switches web pages.



   browser.gesture.twist.right      Browser:NextTab
   browser.gesture.twist.left       Browser:PrevTab
 

 

  

  Two fingers zooms web pages.

browser.gesture.pinch.in         cmd_fullZoomReduce
  browser.gesture.pinch.in.shift   cmd_fullZoomReset
  browser.gesture.pinch.out        cmd_fullZoomEnlarge
  browser.gesture.pinch.out.shift  cmd_fullZoomReset