How to determine in which direction a wizard pane is left

the passfunction of a wizard pane is called for both the next and the previous
button. Typically, only for the next button some kind of processing (validation,
...) is necessary. So, I'm looking for something like 
... if (<wizard's pane next button is clicked> ) ... to extend my passfunctions.

_______________________________________________
Dojo FAQ: http://dojo.jot.com/FAQ
Dojo Book: http://manual.dojotoolkit.org/DojoDotBook
Dojo-interest <at> dojotoolkit.org
http://dojotoolkit.org/mailman/listinfo/dojo-interest