##
win.contentTop

    var t = w.contentTop

The properties "contentLeft" and "contentTop" contain the actual position in screen coordinates of the window's inner displayFrame, i.e. the number of pixels from the top and left corner of the main HTML document. These values are updated whenever a window is moved or resized.
A common use of these properties is in callback functions for drag boxes (see User's Guide 3.2). These functions return the corners of the drag box in absolute screen coordinates. To get the values relative to the window, subtract "contentLeft" and "contentTop" from them.