var upH = 18;			// Height of up-arrow
var upW = 18;			// Width of up-arrow
var downH = 18;			// Height of down-arrow
var downW = 18;			// Width of down-arrow
var dragH = 72;			// Height of scrollbar
var dragW = 52;			// Width of scrollbar
var scrollH = 442;		// Height of scrollbar
var speed = 8;			// Scroll speed

// And now... go to the bottom of the page...

// Browser detection
var dom = document.getElementById ? true:false;
var nn4 = document.layers ? true:false;
var ie4 = document.all ? true:false;

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

var clickUp = false;		// If click on up-arrow
var clickDown = false;		// If click on down-arrow
var clickDrag = false;		// If click on scrollbar
var clickAbove = false;		// If click above scrollbar
var clickBelow = false;		// If click below scrollbar

var timer = setTimeout("",500);	// Repeat variable
var upL;			// Up-arrow X
var upT;			// Up-arrow Y
var downL;			// Down-arrow X
var downT;			// Down-arrow Y
var dragL;			// Scrollbar X
var dragT;			// Scrollbar Y
var rulerL;			// Ruler X
var rulerT;			// Ruler Y
var contentT;			// Content layer Y;
var contentH;			// Content height
var contentClipH;		// Content clip height
var scrollLength;		// Number of pixels scrollbar should move
var startY;			// Keeps track of offset between mouse and span

// Mousedown
function down(e)
{
	if((document.layers && e.which!=1) || (document.all && event.button!=1)) 
	{
		return true; // Enables the right mousebutton
	}
	getMouse(e);
	startY = (mouseY - dragT);
  
	// If click on up-arrow
  	if(mouseX >= upL && (mouseX <= (upL + upW)) && mouseY >= upT && (mouseY <= (upT + upH)))
	{
    		clickUp = true;
		return scrollUp();
	}  
  	// Else if click on down-arrow
  	else if(mouseX >= downL && (mouseX <= (downL + downW)) && mouseY >= downT && (mouseY <= (downT + downH)))
	{
    	clickDown = true;
    	return scrollDown();
	}
  	// Else if click on scrollbar
  	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 click above drag
		if(mouseY < dragT)
		{
			clickAbove = true;
			clickUp = true;
			return scrollUp();
		}
		// Else click below drag
		else
		{
			clickBelow = true;
			clickDown = true;
			return scrollDown();
		}
	}
	// If no scrolling is to take place
	else
	{
		return true;
	}
}

// Drag function
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();
    
		// So ie-pc doesn't select gifs
		if(ie4)
		{
			return false;
		}
	}
}


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

// Reads content layer top
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);
	}
}

// Reads mouse X and Y coordinates
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;
	}
}

// Moves the layer
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";
	}
}

// Scrolls up
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;
}

// Scrolls down
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;
}

// reloads page to position the layers again
function reloadPage()
{
	location.reload();
}

// Preload
function eventLoader()
{
	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);
	}
	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;
	}
	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"; 
	}
	// Number of pixels scrollbar should move
	scrollLength = ((scrollH-dragH)/(contentH-contentClipH));
	// Initializes event capturing
	if(nn4)
	{
		document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP);
		window.onresize = reloadPage;
	}
	document.onmousedown = down;
	document.onmousemove = move;
	document.onmouseup = up;
}