/* This script and many more are available free online at
The JavaScript Source :: http://javascript.internet.com
Created by: Timothy Groves :: http://www.brandspankingnew.net/
Licensed under: Creative Commons License */

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;
}