var dom = document.getElementById ? true:false;
var nn4 = document.layers ? true:false;
var ie4 = document.all ? true:false;
var nn = document.layers ? true:false;
var ie = document.all ? true:false;

/* Beginning of vars to set */
var rulerHeight = 500;
var totalContentHeight = 500;
if (ie) rulerHeight = rulerHeight - 5;
if (ie) totalContentHeight = totalContentHeight - 5;
var dragH = 35; var dragW = 20;
/* End of vars to set */

var num; 
var upH = 11; var upW = 11; var downH = 11; var downW = 11; 
var scrollH = rulerHeight; 
var speedinicial = 5; var veloc=0;

speed=speedinicial;

var mouseY; // Mouse Y position onclick
var mouseX; // Mouse X position onclick

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=0; 
var contentH; var contentClipH; var scrollLength; var startY;


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


function up(){
	clearTimeout(timer);
	speed=3;
	clickUp = false;
	clickDown = false;
	clickDrag = false;
	clickAbove = false;
	clickBelow = false;
	return true;
}


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



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();
			if (veloc<7) { veloc++;
			} else { speed++; veloc=0;}
			
			timer = setTimeout("scrollDown()",25);
		}
	} 
	return false;
	
}

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();
			if (veloc<15) { veloc++;
			} else { speed++; veloc=0;}
			timer = setTimeout("scrollUp()",25);
		}
	}
	return false;
}




function eventLoader(modo){
	
	if(ie4){
		// Up-arrow X and Y variables
		upL = document.all.up.style.pixelLeft;
		upT = document.all.up.style.pixelTop;		
		// Down-arrow X and Y variables
		downL = document.all.down.style.pixelLeft;
		downT = document.all.down.style.pixelTop;
		// Scrollbar X and Y variables
		dragL = document.all.drag.style.pixelLeft;
		dragT = document.all.drag.style.pixelTop;		
		// Ruler Y variable
		rulerT = document.all.ruler.style.pixelTop;		
		// Height of content layer and clip layer
		contentH = parseInt(document.all.content.scrollHeight);
		contentClipH = parseInt(document.all.contentClip.style.height);
		
		
		if ((contentH<totalContentHeight) || (modo==0)) {
			document.all.down.style.visibility = "hidden";
			document.all.ruler.style.visibility = "hidden";
			document.all.drag.style.visibility = "hidden";
			document.all.up.style.visibility = "hidden";
			document.all.fondoscroll.style.visibility = "hidden";
		}
		

	}
	else if(nn4){
		// Up-arrow X and Y variables
		upL = document.up.left;
		upT = document.up.top;		
		// Down-arrow X and Y variables
		downL = document.down.left;
		downT = document.down.top;		
		// Scrollbar X and Y variables
		dragL = document.drag.left;
		dragT = document.drag.top;		
		// Ruler Y variable
		rulerT = document.ruler.top;
		// Height of content layer and clip layer
		contentH = document.contentClip.document.content.clip.bottom;
		contentClipH = document.contentClip.clip.bottom;
		
		alert(contentH);
		if ((contentH<totalContentHeight) || (modo==0)) {
			document.down.visibility = "hidden";
			document.ruler.visibility = "hidden";
			document.drag.visibility = "hidden";
			document.up.visibility = "hidden";
			document.fondoscroll.visibility = "hidden";
		}
		
	}
	else if(dom){
		// Up-arrow X and Y variables
		upL = parseInt(document.getElementById("up").style.left);
		upT = parseInt(document.getElementById("up").style.top);
		// Down-arrow X and Y variables
		downL = parseInt(document.getElementById("down").style.left);
		downT = parseInt(document.getElementById("down").style.top);
		// Scrollbar X and Y variables
		dragL = parseInt(document.getElementById("drag").style.left);
		dragT = parseInt(document.getElementById("drag").style.top);
		// Ruler Y variable
		rulerT = parseInt(document.getElementById("ruler").style.top);
		// Height of content layer and clip layer
		contentH = parseInt(document.getElementById("content").offsetHeight);
		contentClipH = parseInt(document.getElementById("contentClip").offsetHeight);
		document.getElementById("content").style.top = 0 + "px";
		
		if ((contentH<totalContentHeight) || (modo==0)) {
			document.getElementById("down").style.visibility = "hidden";
			document.getElementById("ruler").style.visibility = "hidden";
			document.getElementById("drag").style.visibility = "hidden";
			document.getElementById("up").style.visibility = "hidden";
			document.getElementById("fondoscroll").style.visibility = "hidden";
			
		}
		
		
	}
	// Number of pixels scrollbar should move
	scrollLength = ((scrollH-dragH)/(contentH-contentClipH));
	
		
	// Initializes event capturing
	
	if(nn4){
		self.document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP);
		window.onresize = reloadPage;
	}
	self.document.onmousedown = down;
	self.document.onmousemove = move;
	self.document.onmouseup = up;
}

function reset(){
	if(nn4){
		document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP);
		window.onresize = reloadPage;
	}
	document.onmousedown = down;
	document.onmousemove = move;
	document.onmouseup = up;
}