var _startX = 0;            // mouse starting positions
	var _startY = 0;
	var _offsetX = 0;           // current element offset
	var _offsetY = 0;
	var _lastY = 0;
	var _dragElement;           // needs to be passed from OnMouseDown to OnMouseMove
	var _oldZIndex = 0;         // we temporarily increase the z-index during drag
	//var _debug = $('debug');    // makes life easier
	function ExtractNumber(value){
		var n = parseInt(value);
		return n == null || isNaN(n) ? 0 : n;
	}
	InitDragDrop();
	function InitDragDrop(){
	    document.onmousedown = OnMouseDown;
	    document.onmouseup = OnMouseUp;
	}
	function OnMouseDown(e){
	    // IE is retarded and doesn't pass the event object
	    if (e == null) 
	        e = window.event; 
	    
	    // IE uses srcElement, others use target
	    var target = e.target != null ? e.target : e.srcElement;
	   if(target.id == chkscroll){
		        
		
		    // for IE, left click == 1				//e.button == 1 && window.event != null 
		    // for Firefox, left click == 0			 //e.button == 0
		    
		    if ((e.button == 1 && window.event != null || e.button == 0) && target.className == 'drag') {
		    	
		        // grab the mouse position
		        _startX = e.clientX;
		        _startY = e.clientY;
		        
		        // grab the clicked element's position
		        _offsetX = ExtractNumber(target.style.left);
		        _offsetY = ExtractNumber(target.style.top);
		        
		        // bring the clicked element to the front while it is being dragged
		        _oldZIndex = target.style.zIndex;
		        target.style.zIndex = 10000;
		        
		        // we need to access the element in OnMouseMove
		        _dragElement = target;
		  
		        // tell our code to start moving the element with the mouse
		        document.onmousemove = OnMouseMove;
		     
		        // cancel out any text selections
		        document.body.focus();
		
		        // prevent text selection in IE
		        document.onselectstart = function () { return false; };
		        // prevent IE from trying to drag an image
		        target.ondragstart = function() { return false; };
		        
		        // prevent text selection (except IE)
		        return false;
		        
		    }
		}else{
			
		}
	}
	function OnMouseMove(e){
	    if (e == null) 
	        var e = window.event; 
	
	    // this is the actual "drag code"
	    //_dragElement.style.left = (_offsetX + e.clientX - _startX) + 'px';
	    
	    changetop = _offsetY + e.clientY - _startY;
	    scrollbtnAct(changetop);
	    
	}
	function OnMouseUp(e){
	    if (_dragElement != null)
	    {
	        _dragElement.style.zIndex = _oldZIndex;
	
	        // we're done with these events until the next OnMouseDown
	        document.onmousemove = null;
	        document.onselectstart = null;
	        _dragElement.ondragstart = null;
	
	        // this is how we know we're not dragging      
	        _dragElement = null;
	        
	       // _debug.innerHTML = 'mouse up';
	    }
	}