var request = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("MSXML2.XMLHTTP.3.0");

function createCookie(name,value,days) {
	if (days) {
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}

function eraseCookie(name) {
	createCookie(name,"",-1);
}

function loadStylesheet(type)
{
if (type == 'children')
	{
		createCookie ('childrenStyle', 'true', 1);
    	changeBanner('/education/children.css', '/education/children_banner/logo.html');
	    if (typeof document.body.style.maxHeight != "undefined") {
	  // IE 7, mozilla, safari, opera 9
	  scrollLogo();
		} 
		else 
		{
	  // IE6, older browsers
		}
	}
else if
(type == 'adults')
	{
	eraseCookie('childrenStyle');
	stopScroll();
	changeBanner('/bgs.css', '/header.htm');
	}
}

function checkStylesheetCookie()
{
    if(readCookie('childrenStyle'))
	{
		loadStylesheet('children');
	}
}

function changeBanner(stylesheetURL, bannerURL)
{

	//document.getElementById('header').innerHTML = adults;
	//document.styleSheets[0].href= stylesheetURL;
	var style = document.getElementsByTagName('link')[0];
	var head = document.getElementsByTagName('head')[0];
	head.removeChild(style);
	
	style = document.createElement('link');
	style.type = 'text/css';
	style.rel = 'stylesheet';
	style.href = stylesheetURL;
	style.media = 'screen';
	head.appendChild(style);
	
	request.open("GET", bannerURL, false);
  request.onreadystatechange = function()
  {
    if (request.readyState == 4 && request.status == 200)
    {
      if (request.responseText)
      {
          document.getElementById('header').innerHTML = request.responseText;
      }
    }
  };
  request.send(null);
}

ps=new Object;
ps.intervalId=0;
fps=15;

function scrollLogo(){
	var delayMs=Math.floor(1000/fps);
	setupScrolling();
	ps.intervalId=setInterval('doScroll()',delayMs);
	}

function setupScrolling(){
	var divRef0=document.getElementById('psl_div0');
	var divRef1=document.getElementById('psl_div1');
	var divRef2=document.getElementById('psl_div2');
	var divRef3=document.getElementById('psl_div3');
	divRef0.style.backgroundPosition='0px 50%';
	divRef1.style.backgroundPosition='0px 50%';
	divRef2.style.backgroundPosition='0px 50%';
	divRef3.style.backgroundPosition='2400px 50%';
	}
	
function stopScroll(){
	clearInterval(ps.intervalId);
	fps=0;
	}

function startScroll(){
	if (fps !=0){
	clearInterval(ps.intervalId);
	}
	fps=fps+15;
	var delayMs=Math.floor(1000/fps);
	ps.intervalId=setInterval('doScroll()',delayMs);
	}

function doScroll(){
	
	var divRef0=document.getElementById('psl_div0');
	var divRef1=document.getElementById('psl_div1');
	var divRef2=document.getElementById('psl_div2');
	var divRef3=document.getElementById('psl_div3');
	
	var posnArrayD0=divRef0.style.backgroundPosition.split(' ');
	var posnArrayD1=divRef1.style.backgroundPosition.split(' ');
	var posnArrayD2=divRef2.style.backgroundPosition.split(' ');
	var posnArrayD3=divRef3.style.backgroundPosition.split(' ');
	
	var xPosnD0=parseInt(posnArrayD0[0]);
	var xPosnD1=parseInt(posnArrayD1[0]);
	var xPosnD2=parseInt(posnArrayD2[0]);
	var xPosnD3=parseInt(posnArrayD3[0]);
	
	var newPosnD0='';
	var newPosnD1='';
	var newPosnD2='';
	var newPosnD3='';

	if(xPosnD0 <= 2398){xPosnD0+=2;}
	else{xPosnD0=0;}
	newPosnD0=xPosnD0 + 'px 50%';

	if(xPosnD1 <= 2396){xPosnD1+=4;}
	else{xPosnD1=0;}
	newPosnD1=xPosnD1 + 'px 50%';

	if(xPosnD2 >= 8){xPosnD2-=8;}
	else{xPosnD2=2400;}
	
	yPosn=addVertSweep(xPosnD2);
	newPosnD2=xPosnD2 + 'px ' + yPosn + 'px';
	
	if(xPosnD3 <= 2392){xPosnD3+=8;}
	else{xPosnD3=0;}
	newPosnD3=xPosnD3 + 'px 50%';

	divRef0.style.backgroundPosition=newPosnD0;
	divRef1.style.backgroundPosition=newPosnD1;
	divRef2.style.backgroundPosition=newPosnD2;
	divRef3.style.backgroundPosition=newPosnD3;
	}
	
function addVertSweep(xPosn){
	var rotations=Math.floor(xPosn/360);
	var angleDec=Math.floor(xPosn - (rotations * 360));
	var twoPi=Math.PI*2;
	var angleRad=(angleDec/360)*twoPi;
	var sinRad=Math.sin(angleRad);
	var vertMovementPx=20;
	var defaultY=140;
	var yPosn=Math.floor(defaultY + (sinRad * vertMovementPx));
	return yPosn;
	}