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// 
// Coded by Travis Beckham
// http://www.squidfingers.com | http://www.podlob.com
// If want to use this code, feel free to do so, but please leave this message intact.
//
// ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
// --- version date: 09/29/02 ---------------------------------------------------------

// Utility Functions

var dom = document.getElementById;
var iex = document.all;
var ns4 = document.layers;

function getElement(name, nest){
	nest = nest ? 'document.'+nest+'.' : '';
	var el = dom ? document.getElementById(name) : iex ? document.all[name] : ns4 ? eval(nest+'document.'+name) : false;
	el.css = ns4 ? el : el.style;
	el.getTop = function(){return parseInt(el.css.top) || 0};
	el.setTop = function(y){el.css.top=y};
	el.getHeight = function(){return ns4 ? el.document.height : el.offsetHeight};
	el.getClipHeight = function(){return ns4 ? el.clip.height : el.offsetHeight};
	return el;
}
function getMouse(e){
	return iex ? event.clientY : e.pageY;
}
function fixNetscape(){
	if(NS4origWidth != window.innerWidth || NS4origHeight != window.innerHeight){
		window.location.reload();
	}	
}
if(document.layers){
	NS4origWidth = window.innerWidth;
	NS4origHeight = window.innerHeight;
	window.onresize = fixNetscape;
}

// Scroll Functions
//var trackHeight;
function initScroller(){
	scrollSpeed = 12; // scrolling speed
	dragHeight = 22; // Height of scrollbar drag
	//trackHeight = 136; // Height of scrollbar track; by param transfer
	trackObj = getElement('track'); // Reference to the scrollbar track div
	upObj = getElement('up'); // Reference to the up arrow div
	downObj = getElement('down'); // Reference to the down arrow div
	dragObj = getElement('drag'); // Reference to the scrollbar drag div
	contentMaskObj = getElement('contentMask'); // Reference to the content mask div
	contentObj = getElement('content','contentMask'); // Reference to the content div
	trackTop = dragObj.getTop(); // Scrollbar top contraint
	trackLength = trackHeight-dragHeight; // Adjusted track height
	trackBottom = trackTop+trackLength; // Scrollbar bottom contraint
	contentMaskHeight = contentMaskObj.getClipHeight();// Height of the div that masks the content div
	contentHeight = contentObj.getHeight(); // Height of the content div
	contentLength = contentHeight-contentMaskHeight; // Adjusted content height
	scrollLength = trackLength/contentLength; // Height difference between the scrollbar track and the content
	scrollTimer = null;
	// trackObj.onmousedown = scrollJump;
	upObj.onmousedown = function(){startScroll(scrollSpeed); return false};
	downObj.onmousedown = function(){startScroll(-scrollSpeed); return false};
	dragObj.onmousedown = startDrag;
	dragObj.ondragstart = function(){return false}; // for ie4.5 compatibility
	if(ns4){
		trackObj.captureEvents(Event.MOUSEDOWN);
		upObj.captureEvents(Event.MOUSEDOWN);
		downObj.captureEvents(Event.MOUSEDOWN);
		dragObj.captureEvents(Event.MOUSEDOWN);
	}
}
function startDrag(e){
	dragStartMouse = getMouse(e); // Holds the starting y mouse position
	dragStartOffset = dragObj.getTop(); // Holds the starting top position of the scrollbar drag
	document.onmousemove = drag;
	document.onmouseup = stopDrag;
	if(ns4) document.captureEvents(Event.MOUSEMOVE | Event.MOUSEUP);
	return false;
}
function stopDrag(){
	if(ns4) document.releaseEvents(Event.MOUSEMOVE | Event.MOUSEUP);
	document.onmousemove = null;
	document.onmouseup = null;
}
function drag(e){
	// move drag
	var currentMouse = getMouse(e);
	var mouseDifference = currentMouse-dragStartMouse;
	var dragDistance = dragStartOffset+mouseDifference;
	var dragMovement = (dragDistance<trackTop) ? trackTop : (dragDistance>trackBottom) ? trackBottom : dragDistance;
	dragObj.setTop(dragMovement);
	// move content
	var contentMovement = -(dragMovement-trackTop)*(1/scrollLength);
	contentObj.setTop(contentMovement);
	return false;
}
function startScroll(speed){
	document.onmouseup = stopScroll;
	if(ns4) document.captureEvents(Event.MOUSEUP);
	scroll(speed);
}
function scroll(speed){
	// move content
	var contentMovement = contentObj.getTop()+speed;
	if(contentMovement > 0){
		contentMovement = 0;
	}else if(contentMovement < -contentLength){
		contentMovement = -contentLength;
	}
	contentObj.setTop(contentMovement);
	// move drag
	var dragMovement = contentObj.getTop()*(trackLength/contentLength);
	dragMovement = trackTop-Math.round(dragMovement);
	if(dragMovement < trackTop){
		dragMovement = trackTop;
	}else if(dragMovement > trackBottom){
		dragMovement = trackBottom;
	}
	dragObj.setTop(dragMovement);
	// repeat
	scrollTimer = window.setTimeout('scroll('+speed+')',25);
	return false;
}
function stopScroll(){
	if(scrollTimer){
		window.clearTimeout(scrollTimer);
		scrollTimer = null;
	}
	if(ns4) document.releaseEvents(Event.MOUSEUP);
	document.onmouseup = null;
}
function scrollJump(e){
	// move drag
	var currentMouse = getMouse(e);
	var dragDistance = currentMouse-(dragHeight/2);
	var dragMovement = (dragDistance<trackTop) ? trackTop : (dragDistance>trackBottom) ? trackBottom : dragDistance;
	dragObj.setTop(dragMovement);
	// move content
	var contentMovement = -(dragMovement-trackTop)*(1/scrollLength);
	contentObj.setTop(contentMovement);
	return false;
}

window.onload = initScroller;