var newImages = new Array;

/* ---------------------------------------------------------------------- */
/*  fix PNG backgrounds in IE6 by creating an image to be used as         */
/*  background replacement                                                */
/* ---------------------------------------------------------------------- */
function fixIE6Backgrounds() {
	// make sure it's IE6
	if ((BrowserDetect.browser == "Explorer") && (BrowserDetect.version == "6")) {
		// create and add PNG images
		/*if (refElement = document.getElementById("registerBox"))
			createImage(refElement, "/images/signup_box_background_tcm55-866.png", 0, 0);*/
		/*if (refElement = document.getElementById("conferenceBox"))
			createImage(refElement, "/images/Ipod_tcm55-939.png", 0, 0);*/
		/*if (refElement = document.getElementById("rightColumnBg"))
			createImage(refElement, "/images/right_column_bg_tcm55-941.png", 0, 0);*/
	}
	return;
}

/* ---------------------------------------------------------------------- */
/*  creates and inserts an image to document tree using DOM               */
/* ---------------------------------------------------------------------- */
function createImage(refElement, bgImage, offsetLeft, offsetTop) {
	var bodyElm = document.getElementsByTagName("body")[0];

	/* find coordinates of reference element */
	coords = findPos(refElement);                   // find coordinates of reference element

	/* create new image element */
	img = document.createElement("img");
	img.src = bgImage;                              // set image
	img.style.position = "absolute";                // set absolute positioning or z-index won't work
	img.style.left = coords[0] + offsetLeft + "px"; // set left position
	img.style.top = coords[1] + offsetTop + "px";   // set top position
	img.style.zIndex = 5;                           // set z-index, make sure it ends up below content

	/* append new image to document, push to newImages array so we can keep track of them */
	if (bodyElm.appendChild(img)) {
		newImg = new Object;                          // create object to hold information
		newImg.image = img;                           // reference to the new image
		newImg.offsetLeft = offsetLeft;               // left offset
		newImg.offsetTop = offsetTop;                 // right offset
		newImg.refElement = refElement;               // reference element
		newImages.push(newImg);                       // push to array
	}
	return;
}

/* ---------------------------------------------------------------------- */
/*  handle window resizing                                                */
/* ---------------------------------------------------------------------- */
function onResizeDo() {
	if ((BrowserDetect.browser == "Explorer") && (BrowserDetect.version == "6")) {
		// loop thru all objects in array and re-position them
		for (var i = 0; i < newImages.length; i++) {
			// find coordinates of reference elements
			coords = findPos(newImages[i].refElement);
			newImages[i].image.style.left = coords[0] + newImages[i].offsetLeft + "px";
			newImages[i].image.style.top = coords[1] + newImages[i].offsetTop + "px";
		}
	}
	return;
}

/* ---------------------------------------------------------------------- */
/*  finds left and top position of an element                             */
/* ---------------------------------------------------------------------- */
function findPos(obj) {
	var curleft = curtop = 0;

	if (obj.offsetParent) {
		curleft = obj.offsetLeft
		curtop = obj.offsetTop
		while (obj = obj.offsetParent) {
			curleft += obj.offsetLeft
			curtop += obj.offsetTop
		}
	}
	return [curleft,curtop];
}

/* ---------------------------------------------------------------------- */
/*  browser detect                                                        */
/* ---------------------------------------------------------------------- */
var BrowserDetect = {
	init: function () {
		this.browser = this.searchString(this.dataBrowser) || "An unknown browser";
		this.version = this.searchVersion(navigator.userAgent)
			|| this.searchVersion(navigator.appVersion)
			|| "an unknown version";
		this.OS = this.searchString(this.dataOS) || "an unknown OS";
	},
	searchString: function (data) {
		for (var i=0;i<data.length;i++)	{
			var dataString = data[i].string;
			var dataProp = data[i].prop;
			this.versionSearchString = data[i].versionSearch || data[i].identity;
			if (dataString) {
				if (dataString.indexOf(data[i].subString) != -1)
					return data[i].identity;
			}
			else if (dataProp)
				return data[i].identity;
		}
	},
	searchVersion: function (dataString) {
		var index = dataString.indexOf(this.versionSearchString);
		if (index == -1) return;
		return parseFloat(dataString.substring(index+this.versionSearchString.length+1));
	},
	dataBrowser: [
		{
			string: navigator.userAgent,
			subString: "OmniWeb",
			versionSearch: "OmniWeb/",
			identity: "OmniWeb"
		},
		{
			string: navigator.vendor,
			subString: "Apple",
			identity: "Safari"
		},
		{
			prop: window.opera,
			identity: "Opera"
		},
		{
			string: navigator.vendor,
			subString: "iCab",
			identity: "iCab"
		},
		{
			string: navigator.vendor,
			subString: "KDE",
			identity: "Konqueror"
		},
		{
			string: navigator.userAgent,
			subString: "Firefox",
			identity: "Firefox"
		},
		{
			string: navigator.vendor,
			subString: "Camino",
			identity: "Camino"
		},
		{		// for newer Netscapes (6+)
			string: navigator.userAgent,
			subString: "Netscape",
			identity: "Netscape"
		},
		{
			string: navigator.userAgent,
			subString: "MSIE",
			identity: "Explorer",
			versionSearch: "MSIE"
		},
		{
			string: navigator.userAgent,
			subString: "Gecko",
			identity: "Mozilla",
			versionSearch: "rv"
		},
		{ 	// for older Netscapes (4-)
			string: navigator.userAgent,
			subString: "Mozilla",
			identity: "Netscape",
			versionSearch: "Mozilla"
		}
	],
	dataOS : [
		{
			string: navigator.platform,
			subString: "Win",
			identity: "Windows"
		},
		{
			string: navigator.platform,
			subString: "Mac",
			identity: "Mac"
		},
		{
			string: navigator.platform,
			subString: "Linux",
			identity: "Linux"
		}
	]
};

function onLoadDo() {
	BrowserDetect.init();
	fixIE6Backgrounds();
}

window.onload = onLoadDo;
window.onresize = onResizeDo;