var timer_id, direction, top_limit, bottom_limit, proportion;

function scrollit() {
	var jump_amount = 15;
	//document.getElementById('readout').innerHTML = 'vert_thumb_jump_amount is ' + vert_thumb_jump_amount + ', thumb_jump_amount is ' + thumb_jump_amount + ', right_limit is ' + right_limit + ', proportion is ' + proportion;
	var targ = document.getElementById('newsscrollbox');
	var l = retrieveComputedStyle(targ, 'top');
	l = parseInt(l.substring(0,l.length-2));
	var newl = l + jump_amount * direction;
	if (newl < top_limit) {
		newl = top_limit;
	}
	if (newl > bottom_limit) {
		newl = bottom_limit;
	}
	targ.style.top = newl + 'px';
	//return false;
}

function retrieveComputedStyle(element, styleProperty) {
  var computedStyle = null;
  if (typeof element.currentStyle != "undefined") {
    computedStyle = element.currentStyle;
  }  else {
    computedStyle = document.defaultView.getComputedStyle(element, null);
  }
  return computedStyle[styleProperty];
}

function identifyBrowser() {
  var agent = navigator.userAgent.toLowerCase();

  if (typeof navigator.vendor != "undefined" && navigator.vendor == "KDE" &&
      typeof window.sidebar != "undefined")
  {
    return "kde";
  }
  else if (typeof window.opera != "undefined")
  {
    var version = parseFloat(agent.replace(/.*opera[\/ ]([^ $]+).*/, "$1"));

    if (version >= 7)
    {
      return "opera7";
    }
    else if (version >= 5)
    {
      return "opera5";
    }

    return false;
  }
  else if (typeof document.all != "undefined")
  {
    if (typeof document.getElementById != "undefined")
    {
      var browser = agent.replace(/.*ms(ie[\/ ][^ $]+).*/, "$1").replace(/ /, "");

      if (typeof document.uniqueID != "undefined")
      {
        if (browser.indexOf("5.5") != -1)
        {
          return browser.replace(/(.*5\.5).*/, "$1");
        }
        else
        {
          return browser.replace(/(.*)\..*/, "$1");
        }
      }
      else
      {
        return "ie5mac";
      }
    }

    return false;
  }
  else if (typeof document.getElementById != "undefined")
  {
    if (navigator.vendor.indexOf("Apple Computer, Inc.") != -1)
    {
      if (typeof window.XMLHttpRequest != "undefined")
      {
        return "safari1.2";
      }

      return "safari1";
    }
    else if (agent.indexOf("gecko") != -1)
    {
      return "mozilla";
    }
  }
  return false;
}

function identifyOS()
{
    var agent = navigator.userAgent.toLowerCase();

    if (agent.indexOf("win") != -1)
    {
        return "win";
    }
    else if (agent.indexOf("mac"))
    {
        return "mac";
    }
    else
    {
        return "unix";
    }

    return false;
}

function attachEventListener(target, eventType, functionRef, capture)
{
  if (typeof target.addEventListener != "undefined")
  {
    target.addEventListener(eventType, functionRef, capture);
  }
  else if (typeof target.attachEvent != "undefined")
  {
    target.attachEvent("on" + eventType, functionRef);
  }
  else
  {
    eventType = "on" + eventType;

    if (typeof target[eventType] == "function")
    {
      var oldListener = target[eventType];

      target[eventType] = function()
      {
        oldListener();

        return  functionRef();
      }
    }
    else
    {
      target[eventType] = functionRef;
    }
  }

  return true; 
}

function getScrollingPosition()
{
  //array for X and Y scroll position
  var position = [0, 0];

  //if the window.pageYOffset property is supported
  if(typeof window.pageYOffset != 'undefined')
  {
    //store position values
    position = [
        window.pageXOffset,
        window.pageYOffset
    ];
  }

  //if the documentElement.scrollTop property is supported
  //and the value is greater than zero
  if(typeof document.documentElement.scrollTop != 'undefined'
    && document.documentElement.scrollTop > 0)
  {
    //store position values
    position = [
        document.documentElement.scrollLeft,
        document.documentElement.scrollTop
    ];
  }

  //if the body.scrollTop property is supported
  else if(typeof document.body.scrollTop != 'undefined')
  {
    //store position values
    position = [
        document.body.scrollLeft,
        document.body.scrollTop
    ];
  }

  //return the array
  return position;
}

function getEventTarget(event)
{
  var targetElement = null;

  if (typeof event.target != "undefined")
  {
    targetElement = event.target;
  }
  else
  {
    targetElement = event.srcElement;
  }

  while (targetElement.nodeType == 3 && targetElement.parentNode != null)
  {
    targetElement = targetElement.parentNode;
  }

  return targetElement;
}

function stopDefaultAction(event)
{
  event.returnValue = false;

  if (typeof event.preventDefault != "undefined")
  {
    event.preventDefault();
  }

  return true; 
}

function detachEventListener(target, eventType, functionRef, capture) { 
	if (typeof target.removeEventListener != "undefined") { 
		target.removeEventListener(eventType, functionRef, capture);
	} else if (typeof target.detachEvent != "undefined") { 
		target.detachEvent("on" + eventType, functionRef);
	} else { 
		target["on" + eventType] = null; 
	} 
}
function scrollup() {
	direction = 1;
	return scrollit();
}
function scrolldown() {
	direction = -1;
	return scrollit();
}

function setup() {
	if (typeof document.getElementById != undefined && document.getElementsByTagName != undefined) {
		if (document.getElementById('scrollupbutt') && document.getElementById('scrollupbutt').nodeName.toLowerCase() == 'img') {
			var uplink = document.getElementById('scrollupbutt');
			uplink.style.display = 'block';
			uplink.style.cursor = 'pointer';
			//uplink.onmousedown = function() { direction=1; return scrollit(); };
			addEvent(uplink, 'mousedown', function() {direction=1; return scrollit(); }, false);
		}
		if (document.getElementById('scrolldownbutt') && document.getElementById('scrolldownbutt').nodeName.toLowerCase() == 'img') {
			var downlink = document.getElementById('scrolldownbutt');
			downlink.style.display = 'block';
			downlink.style.cursor = 'pointer';
			downlink.onmousedown = function() { direction = -1; scrollit(); };
		}
		if (document.getElementById('newsscrollbox')) {
			var targ = document.getElementById('newsscrollbox');
			var winie = (identifyOS() == 'win' && identifyBrowser().indexOf('ie') != -1);
			bottom_limit = (winie) ? 20 : 0;
			var l = retrieveComputedStyle(targ, 'height');
			l = parseInt(l.substring(0,l.length-2));
			top_limit = (winie) ? 276 -l : 256 - l;
		}
	}
}

function addEvent(elm, evType, fn, useCapture) {
		if (elm.addEventListener) {
			elm.addEventListener(evType, fn, useCapture);
			return true;
		} else if (elm.attachEvent) {
			var r = elm.attachEvent('on' + evType, fn);
			return r;
		} else {
			elm['on' + evType] = fn;	
		}
}
addEvent(window,'load',setup,false);