enigma1 - 11:55 am on Nov 22, 2011 (gmt 0)

Won't work like that because of the SOP but do you know the url of the button when clicked? If so you can emulate the click by using the src attribute on a resource tag. For example an image tag that points to the url of the button when clicked under normal circumstances. When the browser attempts to load the image he will fire this event automatically.