withinIncludingScrolloffsets :: Position

withinIncludingScrollOffsets(element, x, y) -> Boolean Indicates whether the point x, y (measured from the top-left corner of the document) is within the boundaries of element. Used instead of Position.within whenever element is a child of a scrolling container. Must be called immediately before Position.overlap and immediately after Position.prepare.

This method handles an edge case of Position.within: when element is the child of a scrolling container. (Scriptaculous, for instance, uses it whenever a Draggable’s container is scrollable.) For performance reasons, this method should not be used unless you need this specific edge case.

You must call Position.prepare first, since it calculates offsets that are used by this method.

Prototype API 1.5.0 - prototypejs.org