This article from: http://www.cnblogs.com/mrhgw/archive/2006/11/08/553737.html
Supplement:
Scrollheight: gets the scroll height of an object.
Scrollleft: sets or obtains the distance between the left-side border of the object and the leftmost end of the currently visible content in the window.
Scrolltop: sets or obtains the distance between the top of the object and the top of the visible content in the window.
Scrollwidth: gets the scroll width of an object.
Offsetheight: gets the height of an object relative to the layout or the parent coordinate specified by the parent coordinate offsetparent attribute.
Offsetleft: obtains the left position of the object relative to the layout or the parent coordinate specified by the offsetparent attribute.
Offsettop: obtains the top position event of an object relative to the layout or the parent coordinate specified by the offsettop attribute. the horizontal coordinate event of clientx relative to the document. the vertical coordinate event of clienty relative to the document. the horizontal coordinate event of offsetx relative to the container. offsety is relative to the vertical coordinate of the container document.doc umentelement. event.clientx?document.doc umentelement. the horizontal coordinate of scrolltop relative to the document + The amount of vertical scrolling