/** 
 * 
* 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; 
} 
// Constructor 
_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.stopPending = false; 
	this.stopped = false; 
	this._newfade(); 
} 

// Public methods 

_bsn.Crossfader.prototype.StopFade = function() 
{ 
	if (this.stopped || this.stopPending) { return; } 
	this.stopPending = true; 
	//if (this.nID1) 
	// clearInterval(this.nID1);
} 
	
_bsn.Crossfader.prototype.StartFade = function() 
{ 
	if (this.stopPending) 
	{ 
		this.stopPending = false; 
		
		// Cancel pending stop return; 
	} else if (!this.stopped) 
	{ 
		return; 
	} 
	this._newfade(); 
} 

_bsn.Crossfader.prototype.SetFade = function(newFade) 
{ 
	newFade = parseFloat(newFade); 
	
	if (isNaN(newFade)) 
	{ 
		return "Value provided for new fade time must be numeric"; 
	} 
	
	if (newFade < 0) 
	{ 
		return "Value provided for new fade time cannot be negative"; 
	} 
	
	this.StopFade(); 
	this.nDur = newFade * 1000; 
	this.StartFade(); return ""; 
	
}

_bsn.Crossfader.prototype.SetDelay = function(newDelay) 
{ 
	newDelay = parseFloat(newDelay); 
	if (isNaN(newDelay)) { 
		return "Value provided for new display time must be numeric"; 
	} 
	
	if (newDelay <= 0) 
	{ 
		return "Value provided for new display time must be greater than zero"; 
		
	} 
	
	this.StopFade();
	this.nDelay = newDelay * 1000; 
	this.StartFade(); 
	return ""; 
} 
// Private methods

_bsn.Crossfader.prototype._newfade = function() 
{ 
	if (this.nID1) 
		clearInterval(this.nID1); 
	if (this.stopPending) 
	{ 
		this.stopPending = false; 
		this.stopped = true;

		return; 
		
	} 
	
	this.stopped = false;
	this.nOldAct = this.nAct; 
	this.nAct++; 
	if (!this.aDivs[this.nAct]) return; 
	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; 
	
}