/**

 *  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

 *
 * The constructor takes three variables: 
 *   an array containing the ids of the divs to be faded, 
 *   the fade time (in milliseconds), 
 *   and the delay between fades (also in milliseconds)
 *  call with <script type="text/javascript">
 *	      var cf = new Crossfader( new Array('cf1','cf2','cf3'), 500, 2000 );
 *            </script>
 *

 */
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;

}