Can someone canonically differentiate between scrollTop and scrollHeight?

Question

For example,

function fnCheckScroll(){        var iNewHeight = oDiv.scrollHeight;     var iscrolTop = oDiv.scrollTop;      alert("The value of the scrollHeight property is: "  + iNewHeight + "px");      alert("The value of the scrollTop property is: " + iscrolTop + "px");         }  <div id="oDiv" style="overflow: scroll; height= 100px; width= 250px; text-align: left"> Hello<br> </div> 

In IE 8, the value of scrollTop is always: 0 - returns 0 for scrollTop (even after scrolling)?

Answer 1

Ref: scrollTop, scrollHeight, clientHeight

Answer 2

See the MDC articles, scrollTop and scrollHeight. In summary, scrollTop is how much it's currently scrolled, and scrollHeight is the total height, including content scrolled out of view.