// Fade interval in milliseconds
// Make this larger if you experience performance issues
Fadomatic.INTERVAL_MILLIS = 75;

// Creates a fader
// element - The element to fade
// speed - The speed to fade at, from 0.0 to 100.0
// initialOpacity (optional, default 100) - element's starting opacity, 0 to 100
// minOpacity (optional, default 0) - element's minimum opacity, 0 to 100
// maxOpacity (optional, default 0) - element's minimum opacity, 0 to 100
function Fadomatic (element, rate, initialOpacity, minOpacity, maxOpacity) {
  this._element = element;
  this._intervalId = null;
  this._rate = rate;
  this._isFadeOut = true;

  // Set initial opacity and bounds
  // NB use 99 instead of 100 to avoid flicker at start of fade
  this._minOpacity = 0;
  this._maxOpacity = 99;
  this._opacity = 99;

  if (typeof minOpacity != 'undefined') {
    if (minOpacity < 0) {
      this._minOpacity = 0;
    } else if (minOpacity > 99) {
      this._minOpacity = 99;
    } else {
      this._minOpacity = minOpacity;
    }
  }

  if (typeof maxOpacity != 'undefined') {
    if (maxOpacity < 0) {
      this._maxOpacity = 0;
    } else if (maxOpacity > 99) {
      this._maxOpacity = 99;
    } else {
      this._maxOpacity = maxOpacity;
    }

    if (this._maxOpacity < this._minOpacity) {
      this._maxOpacity = this._minOpacity;
    }
  }
  
  if (typeof initialOpacity != 'undefined') {
    if (initialOpacity > this._maxOpacity) {
      this._opacity = this._maxOpacity;
    } else if (initialOpacity < this._minOpacity) {
      this._opacity = this._minOpacity;
    } else {
      this._opacity = initialOpacity;
    }
  }

  // See if we're using W3C opacity, MSIE filter, or just
  // toggling visiblity
  if(typeof element.style.opacity != 'undefined') {

    this._updateOpacity = this._updateOpacityW3c;

  } else if(typeof element.style.filter != 'undefined') {

    // If there's not an alpha filter on the element already,
    // add one
    if (element.style.filter.indexOf("alpha") == -1) {

      // Attempt to preserve existing filters
      var existingFilters="";
      if (element.style.filter) {
        existingFilters = element.style.filter+" ";
      }
      element.style.filter = existingFilters+"alpha(opacity="+this._opacity+")";
    }

    this._updateOpacity = this._updateOpacityMSIE;
    
  } else {

    this._updateOpacity = this._updateVisibility;
  }

  this._updateOpacity();
}

// Initiates a fade out
Fadomatic.prototype.fadeOut = function () {
  this._isFadeOut = true;
  this._beginFade();
}

// Initiates a fade in
Fadomatic.prototype.fadeIn = function () {
  this._isFadeOut = false;
  this._beginFade();
}

// Makes the element completely opaque, stops any fade in progress
Fadomatic.prototype.show = function () {
  this.haltFade();
  this._opacity = this._maxOpacity;
  this._updateOpacity();
}

// Makes the element completely transparent, stops any fade in progress
Fadomatic.prototype.hide = function () {
  this.haltFade();
  this._opacity = 0;
  this._updateOpacity();
}

// Halts any fade in progress
Fadomatic.prototype.haltFade = function () {

  clearInterval(this._intervalId);
}

// Resumes a fade where it was halted
Fadomatic.prototype.resumeFade = function () {

  this._beginFade();
}

// Pseudo-private members

Fadomatic.prototype._beginFade = function () {

  this.haltFade();
  var objref = this;
  this._intervalId = setInterval(function() { objref._tickFade(); },Fadomatic.INTERVAL_MILLIS);
}

Fadomatic.prototype._tickFade = function () {

  if (this._isFadeOut) {
    this._opacity -= this._rate;
    if (this._opacity < this._minOpacity) {
      this._opacity = this._minOpacity;
	  this._isFadeOut = false;
      //this.haltFade();
    }
  } else {
    this._opacity += this._rate;
    if (this._opacity > this._maxOpacity ) {
      this._opacity = this._maxOpacity;
	  this._isFadeOut = true;
      //this.haltFade();
    }
  }

  this._updateOpacity();
}

Fadomatic.prototype._updateVisibility = function () {
  
  if (this._opacity > 0) {
    this._element.style.visibility = 'visible';
  } else {
    this._element.style.visibility = 'hidden';
  }
}

Fadomatic.prototype._updateOpacityW3c = function () {
  
  this._element.style.opacity = this._opacity/100;
  this._updateVisibility();
}

Fadomatic.prototype._updateOpacityMSIE = function () {
  
  this._element.filters.alpha.opacity = this._opacity;
  this._updateVisibility();
}

Fadomatic.prototype._updateOpacity = null;

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

//setup onload function
if (bw.isW3){
if(typeof window.addEventListener != 'undefined')
{
	//.. gecko, safari, konqueror and standard
	window.addEventListener('load', generic, false);
}
else if(typeof document.addEventListener != 'undefined')
{
	//.. opera 7
	document.addEventListener('load', generic, false);
}
else if(typeof window.attachEvent != 'undefined')
{
	//.. win/ie
	window.attachEvent('onload', generic);
}

//** remove this condition to degrade older browsers
else
{
	//.. mac/ie5 and anything else that gets this far
	
	//if there's an existing onload function
	if(typeof window.onload == 'function')
	{
		//store it
		var existing = onload;
		
		//add new onload handler
		window.onload = function()
		{
			//call existing onload function
			existing();
			
			//call generic onload function
			generic();
		};
	}
	else
	{
		//setup onload function
		window.onload = generic;
	}
}
}

var fader1,fader2,fader3
var box1,box2,box3

function generic(){
	box1=MM_findObj('box1');
	box2=MM_findObj('box2');
	box3=MM_findObj('box3');
	
	fader1 = new Fadomatic(box1, 2, 10,10);
	fader1.fadeIn();
	fader2 = new Fadomatic(box2, 2, 100,10);
	fader2.fadeOut();
	fader3 = new Fadomatic(box3, 2, 55,10);
	fader3.fadeIn();
}