var ie6 = false;
var prevWW = -1;
var prevWH = -1;
var prevImgH = -1;

/*-----------------------------------------------------------------------------------*/
function init(dir) {
	var backs = new Array(7); //8);
	backs[0] = {src:'images/1100BG-devos.jpg', caption:'DeVos Performance Hall'};
	backs[1] = {src:'images/1100BG-dtwnGR.jpg', caption:'Downtown Grand Rapids'};
	backs[2] = {src:'images/1100BG-imperballrm.jpg', caption:'Imperial Ballroom,<br/>Awmay Grand Plaza Hotel'};
	backs[3] = {src:'images/1100BG-JWlobby.jpg', caption:'JW Marriott Grand Rapids'};
	backs[4] = {src:'images/1100BG-presballrm.jpg', caption:'Gerald R. and Betty Ford<br/>Presidential Ballroom,<br/>Awmay Grand Plaza Hotel'};
	backs[5] = {src:'images/1100BG-sixonesix.jpg', caption:'six.one.six,<br/>JW Marriott Grand Rapids'};
	backs[6] = {src:'images/1100BG-skyline.jpg', caption:'Downtown Grand Rapids'};
	//backs[7] = {src:'images/1100BG-pantlind.jpg', caption:'Awmay Grand Plaza Hotel'}; //too bright for IE6
	
	var i = Math.floor(Math.random()*backs.length);
	document.getElementById('bgimg').src = dir+backs[i].src;
	
	var c = document.getElementById('caption');
	if ( c ) { c.innerHTML = backs[i].caption; }
	
	setInterval("resizeBg()", 200);
}

/*-----------------------------------------------------------------------------------*/
function setIe6() { ie6 = true; }

/*-----------------------------------------------------------------------------------*/
function resizeBg() {
	var ww = Math.max(950, getWindowW());
	var wh = Math.max(632, getWindowH());
	
	var img = document.getElementById('bgimg');
	var imgW = img.width;
	var imgH = img.height;
	
	if ( ww == prevWW && wh == prevWH && imgH == prevImgH ) { return; }
	prevWW = ww;
	prevWH = wh;
	prevImgH = imgH;
	
	img.style.width = '0px';
	img.style.height = '0px';
	img.style.display = '';
	
	if ( (ww/imgW)*imgH < wh ) {
		img.style.height = wh+'px';
		img.style.width = 'auto';
	}
	else {
		img.style.width = ww+'px';
		img.style.height = 'auto';
	}
	
	if ( ie6 ) {
		var fs = document.getElementById('fullscreenbg');
		var mb = document.getElementById('menubar');
		fs.style.width = mb.style.width = ww+'px';
		fs.style.height = wh+'px';
	}
}

/*-----------------------------------------------------------------------------------*/
function getWindowW() {
	if ( typeof(window.innerWidth) == 'number' ) { return window.innerWidth; }
	
	var de = document.documentElement;
	if ( de && de.clientWidth ) { return de.clientWidth; }
	
	var db = document.body;
	if ( db && db ) { return db.clientWidth; }
}

/*-----------------------------------------------------------------------------------*/
function getWindowH() {
	if ( typeof(window.innerHeight) == 'number' ) { return window.innerHeight; }
	
	var de = document.documentElement;
	if ( de && de.clientHeight ) { return de.clientHeight; }
	
	var db = document.body;
	if ( db && db.clientHeight ) { return db.clientHeight; }
}