/**
 *  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;

}