//preload the rollover images
if (document.images){
	rList=[];
	nList=[];
	
	//preload bg images first
	var h=new Image();
	h.src='images/header.jpg';
	
	var bg=new Image();
	bg.src='images/lnav-bg.jpg';
	
	var vbg=new Image();
	vbg.src='images/vid-bg.jpg';
	
	for (i = 1; i < 13; i++) {
		var num=i;
		if(num<10)num='0'+i;
		
		//preload top rollover images
		var timg=new Image();
		timg.src='images/numbers/tnum'+num+'_r.gif';
		rList.push(timg);
		
		//store original names		
		nList.push('images/numbers/tnum'+num+'.gif');
		
		//preload side nav rollovers
		
		var rg = new Image();
		rg.src='images/sidenav/num'+(i)+'_r.gif';
	}
	
}

//functions to handle rollover text in the header
var pagename;
var lessonnum;
function setTitle(itxt, chnum, mnum){
	pagename=itxt;
	lessonnum=mnum;
	document.getElementById("tiparea").innerHTML=itxt;
	var el='i'+(chnum+1);
	document.getElementById(el).src=rList[chnum].src;
	
	if (mnum > 0) {
		el = 'nav' + (mnum - 1);
		document.getElementById(el).src = 'images/sidenav/num' + (mnum) + '_r.gif';
	}
	
}
function showme(inum){
	var el = document.getElementById('tip'+inum);
	if (el != null) {		
		el.style.display = 'block';
	}
}
function hideme(inum){
	var el = document.getElementById('tip'+inum);
	if (el != null) {		
		el.style.display = 'none';
	}
}
function chapterRoll(inum){
	triggerFlash();//call the play sound function on rollovers
	showme(inum);
	var el='i'+(inum+1);
	document.getElementById(el).src=rList[inum].src;
}

function chapterOut(itxt, inum){
	hideme(inum);
	var el='i'+(inum+1);
	if (itxt != pagename) {
		document.getElementById(el).src = nList[inum];
	} else {
		document.getElementById(el).src = rList[inum].src;
	}
}

function sideRoll(inum, isnd){
	if(isnd==1)triggerFlash(1);//call the play sound function on rollovers
	var el='nav'+(inum);	
	document.getElementById(el).src='images/sidenav/num'+(inum+1)+'_r.gif';
}

function sideOut(inum){
	var el='nav'+(inum);
	if ((inum+1) != lessonnum) {
		document.getElementById(el).src='images/sidenav/num'+(inum+1)+'.gif';
	} else {
		document.getElementById(el).src='images/sidenav/num'+(inum+1)+'_r.gif';
	}
	
}

function resroll(){
	triggerFlash(2)
	document.getElementById("resimg").src="images/sidenav/res_roll.gif";
}
function resout(){
	document.getElementById("resimg").src="images/sidenav/res.gif";
}
function resdwn(){
	document.getElementById("resimg").src="images/sidenav/res_dwn.gif";
}
function resup(){
	document.getElementById("resimg").src="images/sidenav/res_roll.gif";
	getSWFInstance("vid").showResources();
}

//trigger sounds in flash
function getSWFInstance(swfName) {
	if (navigator.appName.indexOf("Microsoft") != -1) {
		return window[swfName];
	} else {
		return document[swfName];
	}
}


function triggerFlash(inum){
	getSWFInstance("sound").playsound(inum);	
}