Resizing div with drag

[Tristan Van Poucke]

I have been working on this way to resize a div by dragging a part of it down.
I only want the div to resize 20px at a time and for this I have used following method:

    
 
if(_lastStop == null || _lastStop == "" || _lastStop == 20)
    {
            _lastStop = _startY;
    }
      
  
    document.getElementById("offsetDragable").value = e.clientY
    if(e.clientY - _lastStop >= 10)
    {
            _Resize.style.height = _Resize.offsetHeight + 20 + 'px';
 
            _lastStop = _Resize.offsetTop + _Resize.offsetHeight;
     }
     if(e.clientY - _lastStop <= -10)
    {
            _Resize.style.height = _Resize.offsetHeight - 20 + 'px';
 
            _lastStop = _Resize.offsetTop + _Resize.offsetHeight;
     }
  

_startY : Y position of mouse where started dragging.
_Resize : div that is to be resized.
_lastStop: position of last resize.
e.clientY: current position of mouse.

This works perfectly. But when I scroll the page down a bit, and start to resize the div, pulling it down , it gets smaller first and THEN it gets bigger. Does anyone have any Idea why this is?
[ October 01, 2008: Message edited by: Bear Bibeault ]