/**
 * 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;
}