var dom = document.getElementById ? true:false;
var nn4 = document.layers ? true:false;
var ie4 = document.all ? true:false;
var opera = (window.opera) ? true:false;
var mouseY;
var mouseX;
var clickUp = false;
var clickDown = false;
var clickDrag = false;
var clickAbove = false;
var clickBelow = false;
var timer = setTimeout("",500);
var upL;
var upT;
var downL;
var downT;
var dragL;
var dragT;
var rulerL;
var rulerT;
var contentT;
var contentH;
var contentClipH;
var scrollLength;
var startY;

function down(e){
    if(opera){}
	else{if((document.layers && e.which!=1) || (document.all && event.button!=1))return true;}	
	getMouse(e);
	startY = (mouseY - dragT);
	if(mouseX >= upL && (mouseX <= (upL + upW)) && mouseY >= upT && (mouseY <= (upT + upH))){
		clickUp = true;
		return scrollUp();
	}	
	else if(mouseX >= downL && (mouseX <= (downL + downW)) && mouseY >= downT && (mouseY <= (downT + downH))){
		clickDown = true;
		return scrollDown();
	}
	else if(mouseX >= dragL && (mouseX <= (dragL + dragW)) && mouseY >= dragT && (mouseY <= (dragT + dragH))){
		clickDrag = true;
		return false;
	}
	else if(mouseX >= dragL && (mouseX <= (dragL + dragW)) && mouseY >= rulerT && (mouseY <= (rulerT + scrollH))){
		if(mouseY < dragT){
			clickAbove = true;
			clickUp = true;
			return scrollUp();
		}
		else{
			clickBelow = true;
			clickDown = true;
			return scrollDown();
		}
	}
	else{
		return true;
	}
}

function move(e){
	if(clickDrag && contentH > contentClipH){
		getMouse(e);
		dragT = (mouseY - startY);
		if(dragT < (rulerT))
			dragT = rulerT;		
		if(dragT > (rulerT + scrollH - dragH))
			dragT = (rulerT + scrollH - dragH);
		contentT = ((dragT - rulerT)*(1/scrollLength));
		contentT = eval('-' + contentT);
		moveTo();
		if(ie4)
			return false;
	}
}

function up(){
	clearTimeout(timer);
	clickUp = false;
	clickDown = false;
	clickDrag = false;
	clickAbove = false;
	clickBelow = false;
	return true;
}

function getT(){
	if(ie4) contentT = document.all.contentspan.style.pixelTop;
	else if(nn4) contentT = document.contentClip.document.contentspan.top;
	else if(dom) contentT = parseInt(document.getElementById("contentspan").style.top);
}

function getMouse(e){
	if(ie4){
		mouseY = event.clientY + document.body.scrollTop;
		mouseX = event.clientX + document.body.scrollLeft;
	}
	else if(nn4 || dom){
		mouseY = e.pageY;
		mouseX = e.pageX;
	}
}

function moveTo(){
	if(ie4){
		document.all.contentspan.style.top = contentT;
		document.all.ruler.style.top = dragT;
		document.all.drag.style.top = dragT;
	}
	else if(nn4){
		document.contentClip.document.contentspan.top = contentT;
		document.ruler.top = dragT;
		document.drag.top = dragT;
	}
	else if(dom){
		document.getElementById("contentspan").style.top = contentT + "px";
		document.getElementById("drag").style.top = dragT + "px";
		document.getElementById("ruler").style.top = dragT + "px";
	}
}

function scrollUp(){
	getT();
	if(clickAbove){
		if(dragT <= (mouseY-(dragH/2)))
			return up();
	}
	if(clickUp){
		if(contentT < 0){		
			dragT = dragT - (speed*scrollLength);			
			if(dragT < (rulerT))
				dragT = rulerT;
			contentT = contentT + speed;
			if(contentT > 0)
				contentT = 0;
			moveTo();
			timer = setTimeout("scrollUp()",25);
		}
	}
	return false;
}

function scrollDown(){
	getT();
	if(clickBelow){
		if(dragT >= (mouseY-(dragH/2)))
			return up();
	}
	if(clickDown){
		if(contentT > -(contentH - contentClipH)){			
			dragT = dragT + (speed*scrollLength);
			if(dragT > (rulerT + scrollH - dragH))
				dragT = (rulerT + scrollH - dragH);			
			contentT = contentT - speed;
			if(contentT < -(contentH - contentClipH))
				contentT = -(contentH - contentClipH);
			moveTo();
			timer = setTimeout("scrollDown()",25);
		}
	}
	return false;
}

function reloadPage(){
	location.reload();
}

function eventLoader(){
	if(ie4){
		upL = document.all.up.style.pixelLeft;
		upT = document.all.up.style.pixelTop;		
		downL = document.all.down.style.pixelLeft;
		downT = document.all.down.style.pixelTop;
		dragL = document.all.drag.style.pixelLeft;
		dragT = document.all.drag.style.pixelTop;		
		rulerT = document.all.ruler.style.pixelTop;		
		contentH = parseInt(document.all.contentspan.scrollHeight);
		contentClipH = parseInt(document.all.contentClip.style.height);
	}
	else if(nn4){
		upL = document.up.left;
		upT = document.up.top;		
		downL = document.down.left;
		downT = document.down.top;		
		dragL = document.drag.left;
		dragT = document.drag.top;		
		rulerT = document.ruler.top;
		contentH = document.contentClip.document.contentspan.clip.bottom;
		contentClipH = document.contentClip.clip.bottom;
	}
	else if(dom){
		upL = parseInt(document.getElementById("up").style.left);
		upT = parseInt(document.getElementById("up").style.top);
		downL = parseInt(document.getElementById("down").style.left);
		downT = parseInt(document.getElementById("down").style.top);
		dragL = parseInt(document.getElementById("drag").style.left);
		dragT = parseInt(document.getElementById("drag").style.top);
		rulerT = parseInt(document.getElementById("ruler").style.top);
		contentH = parseInt(document.getElementById("contentspan").offsetHeight);
		contentClipH = parseInt(document.getElementById("contentClip").offsetHeight);
		document.getElementById("contentspan").style.top = 0 + "px";
	}
	scrollLength = ((scrollH-dragH)/(contentH-contentClipH));
	if(nn4){
		document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP);
		window.onresize = reloadPage;
	}
	
	if (scrollLength > 0){
        document.onmousedown = down;
        document.onmousemove = move;
        document.onmouseup = up;
        document.getElementById("drag").style.visibility = "visible";
        document.getElementById("ruler").style.visibility = "visible";
    }
}