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;

}