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++){
		tdiv=document.getElementById(divs[i]);
		tdiv.style.opacity = 0;
		tdiv.style.position = "absolute";
		tdiv.style.filter = "alpha(opacity=0)";
		tdiv.style.visibility = "hidden";
		tdiv.style.zIndex=10;
	}
	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";
	document.getElementById( this.aDivs[this.nAct] ).style.zIndex=20;
	if(this.nOldAct>-1){
		document.getElementById( this.aDivs[this.nOldAct]).style.zIndex=10;
	}
	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;
	tOld=document.getElementById(this.aDivs[this.nOldAct]);
	tNew=document.getElementById(this.aDivs[this.nAct]);
	if(document.all){
		tNew.style.filter = "alpha(opacity="+ieop+")";
	}else{
		tNew.style.opacity = op;
	}
	if (this.nTime == this.nDur){
		clearInterval( this.nID2 );
		if (this.nOldAct > -1){
			tOld.style.visibility = "hidden";
			if(document.all){
				tOld.style.filter = "alpha(opacity=0)";
			}else{
				tOld.style.opacity = 0;
			}
		}
		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;
}