See this post for more info: http://ankitbparekh.blogspot.com/2010/04/unknown-runtime-error-ie-in-prototypejs.html
…lement. the current method only looks at the 'onchange' property of the target element. this means that if any events are add using Event.observe (in prototype - or addEventListener / attachEvent outside prototype), they are not fired when the date is selected. this is updated to fire the onchange event on the element, rather than calling the onchange function.