/**
 *  author:		Timothy Groves - http://www.brandspankingnew.net
 *	version:	1.3 - 2006-11-02
 *				1.2 - 2006-11-01
 *				1.1 - 2006-09-29
 *				1.0 - 2006-09-25
 *
 *	requires:	nothing
 *
 */
var useBSNns;


if (useBSNns)
{	if (typeof(bsn) == "undefined")
		bsn = {}
	
var _bsn = bsn;}else
{
	var _bsn = this;
}





_bsn.Crossfader = function (divs, fadetime, delay )
{
	
	this.nAct = -1;

	this.aDivs = divs;	
	for (var i=0;i<divs.length;i++)
	{		document.getElementById(divs[i]).style.opacity = 0;

		document.getElementById(divs[i]).style.position = "absolute";

		document.getElementById(divs[i]).style.filter = "alpha(opacity=0)";

		document.getElementById(divs[i]).style.visibility = "hidden";
	}

	
	this.nDur = fadetime;
	this.nDelay = delay;

		
	this._newfade();
}



_bsn.Crossfader.prototype._newfade = function()
{	if (this.nID1)
		clearInterval(this.nID1);

	
	this.nOldAct = this.nAct;

	this.nAct++;

	if (!this.aDivs[this.nAct])	this.nAct = 0;

	
	if (this.nAct == this.nOldAct)
		return false;

	
	document.getElementById( this.aDivs[this.nAct] ).style.visibility = "visible";
	
	this.nInt = 50;
	this.nTime = 0;

	
	var p=this;

	this.nID2 = setInterval(function() { p._fade() }, this.nInt);
}



_bsn.Crossfader.prototype._fade = function()
{
	this.nTime += this.nInt;

	
	var ieop = Math.round( this._easeInOut(this.nTime, 0, 1, this.nDur) * 100 );

	var op = ieop / 100;

	document.getElementById( this.aDivs[this.nAct] ).style.opacity = op;

	document.getElementById( this.aDivs[this.nAct] ).style.filter = "alpha(opacity="+ieop+")";

	
	if (this.nOldAct > -1)
	{
		document.getElementById( this.aDivs[this.nOldAct] ).style.opacity = 1 - op;

		document.getElementById( this.aDivs[this.nOldAct] ).style.filter = "alpha(opacity="+(100 - ieop)+")";

	}
	
	
if (this.nTime == this.nDur)
	{		clearInterval( this.nID2 );

		
		if (this.nOldAct > -1)

			document.getElementById( this.aDivs[this.nOldAct] ).style.visibility = "hidden";
	
		
		var p=this;

		this.nID1 = setInterval(function() { p._newfade() }, this.nDelay);

	}
}


_bsn.Crossfader.prototype._easeInOut = function(t,b,c,d)
{
	return c/2 * (1 - Math.cos(Math.PI*t/d)) + b;
}