While trying to build a flyout style menu that animated the opening and closing of menus I ran into problems with the clip style property. The default value of clip is auto, however only firefox understands style.clip = ‘auto’, Safari and IE don’t honor it. By changing it to style.clip = null I got it to work in Firefox and Safari, but no go in IE. So for IE I tried style.clip = ‘rect(auto, auto, auto, auto)’ which worked in IE7 but not in IE6. So finally, by adding style.display = ‘inline-block’ to IE6 I was finally able to remove the clipping style.
As an aside, in CSS the definitive Guide it says rect(0 auto auto 0) is the same as specifing no change to the clipping region, but it didn’t work for right-aligned menus.