// lower number fades faster, higher number fades slower...
var fadeSpeed = 50; 
var imageIndex = 0;

function getElementById(id)
{
   var elem = document.getElementById(id);

   if(elem == null)
   {
      elem = window.parent.document.getElementById(id);
   }   

   if(elem == null)
   {
      alert('sorry, elem is still null, id "'+id+'" not found.');
      return false;
   }
   
   return elem;
}


/*
* Author:mz
* Date: 	6/15/06
* Desc:  Handles fading an element in
*/
function fadeIn(pElementID, pOpacity)
{
   var elem = getElementById(pElementID);
   
   // no need to fade in, the element already has
   // full opacity.  Return immediately.
   // elem.style.opacity = pOpacity/10;
   //   elem.style.filter = 'alpha(opacity=' + (pOpacity * 10) + ')';
   //if(elem.style.opacity >= 1 || elem.style.filter == 'alpha(opacity=100)')
   //{
   //   return true;
   //}

   if(pOpacity == undefined)
   {
      pOpacity = 0;
   }

	if(pOpacity < 10)
	{
		pOpacity += .5;
      elem.style.opacity = pOpacity/10;
      elem.style.filter = 'alpha(opacity=' + (pOpacity * 10) + ')';
    
		setTimeout("fadeIn('"+pElementID+"',"+pOpacity+")",fadeSpeed);
	}
	else
	{
	  setTimeout("fadeOut('home-hero-image')",2000);
	}	
}

/*
* Author:mz
* Date:  6/15/06
* Desc:  Handles fading an element out
*/
function fadeOut(pElementID, pOpacity)
{
   var elem = getElementById(pElementID);
   
   // no need to fade in, the element already has
   // full opacity.  Return immediately.
   // elem.style.opacity = pOpacity/10;
   //   elem.style.filter = 'alpha(opacity=' + (pOpacity * 10) + ')';
   //if(elem.style.opacity <= 0 || elem.style.filter == 'alpha(opacity=0)')
   //{
   //   return true;
   //}
   
   if(pOpacity == undefined)
   {
      pOpacity = 10;
   }

   if(pOpacity > 0)
   {
      pOpacity -= .5;
      elem.style.opacity = pOpacity/10;
      elem.style.filter = 'alpha(opacity=' + (pOpacity * 10) + ')';
    
      setTimeout("fadeOut('"+pElementID+"',"+pOpacity+")",fadeSpeed);
   }  
   else
   {      
      fadeInImage();
   }
}

function fadeInImage()
{   
   var images = new Array('hero2-ge.jpg', 'hero2-logos.jpg', 'hero2-ta.jpg', 'hero2-wo.jpg', 'hero2-dc.jpg', 'hero2-tri.jpg');
   var divElem = getElementById('home-hero-image');
   
   divElem.style.backgroundImage = 'url(./img/fade_images/'+images[imageIndex]+')';

   if(imageIndex == images.length - 1)
   {
      imageIndex = 0;
   }
   else
   {
      imageIndex++;
   }

   fadeIn('home-hero-image');
}