function scheduleImageRotation()
{
	// this script causes IE to flake out
	if(isInternetExplorer()) return;
	var banner = document.getElementById('banner');
	var image = getNextImage(banner,'ya-ya-logo.jpg');
	rotateImage(banner,image);
	setTimeout('scheduleImageRotation()',6000);
}

function isInternetExplorer()
{
	if (navigator.appName == "Microsoft Internet Explorer") return true;
	return false;
}

function getNextImage(element,name)
{
	var start = element.src.lastIndexOf('/');
	var stop = element.src.length
	var image = element.src.substr(start + 1,stop);
	var base = '/sites/yayanetwork.org/themes/yaya/images/';
	var new_image;
	if(image == 'b.' + name)
	{
		return base + 'a.' + name;
	}
	else
	{
		return base + 'b.' + name;
	}
}

function rotateImage(element,new_image)
{
	crossfade(element, new_image, '3');
}

if(!isInternetExplorer())
{

	// IXF1.11 :: Image cross-fade 
	// *****************************************************
	// DOM scripting by brothercake -- http://www.brothercake.com/
	//******************************************************
	//global object
	var ixf = { 'clock' : null, 'count' : 1 }
	/*******************************************************



	/*****************************************************************************
	 List the images that need to be cached
	*****************************************************************************/

	ixf.imgs = [
		'buttons/udm4-whitebutton88x31.gif',
		'buttons/udm4-greenbutton88x31.gif',
		'buttons/udm4-purplebutton88x31.gif'
		];

	/*****************************************************************************
	*****************************************************************************/



	//cache the images
	ixf.imgsLen = ixf.imgs.length;
	ixf.cache = [];
	for(var i=0; i<ixf.imgsLen; i++)
	{
		ixf.cache[i] = new Image;
		ixf.cache[i].src = ixf.imgs[i];
	}


	//crossfade setup function
	function crossfade()
	{
		//if the timer is not already going
		if(ixf.clock == null)
		{
			//copy the image object 
			ixf.obj = arguments[0];
			
			//copy the image src argument 
			ixf.src = arguments[1];
			
			//store the supported form of opacity
			if(typeof ixf.obj.style.opacity != 'undefined')
			{
				ixf.type = 'w3c';
			}
			else if(typeof ixf.obj.style.MozOpacity != 'undefined')
			{
				ixf.type = 'moz';
			}
			else if(typeof ixf.obj.style.KhtmlOpacity != 'undefined')
			{
				ixf.type = 'khtml';
			}
			else if(typeof ixf.obj.filters == 'object')
			{
				//weed out win/ie5.0 by testing the length of the filters collection (where filters is an object with no data)
				//then weed out mac/ie5 by testing first the existence of the alpha object (to prevent errors in win/ie5.0)
				//then the returned value type, which should be a number, but in mac/ie5 is an empty string
				ixf.type = (ixf.obj.filters.length > 0 && typeof ixf.obj.filters.alpha == 'object' && typeof ixf.obj.filters.alpha.opacity == 'number') ? 'ie' : 'none';
			}
			else
			{
				ixf.type = 'none';
			}
			
			//change the image alt text if defined
			if(typeof arguments[3] != 'undefined' && arguments[3] != '')
			{
				ixf.obj.alt = arguments[3];
			}
			
			//if any kind of opacity is supported
			if(ixf.type != 'none')
			{
				//create a new image object and append it to body
				//detecting support for namespaced element creation, in case we're in the XML DOM
				ixf.newimg = document.getElementsByTagName('body')[0].appendChild((typeof document.createElementNS != 'undefined') ? document.createElementNS('http://www.w3.org/1999/xhtml', 'img') : document.createElement('img'));

				//set positioning classname
				ixf.newimg.className = 'idupe';
				
				//set src to new image src
				ixf.newimg.src = ixf.src

				//move it to superimpose original image
				ixf.newimg.style.left = ixf.getRealPosition(ixf.obj, 'x') + 'px';
				ixf.newimg.style.top = ixf.getRealPosition(ixf.obj, 'y') + 'px';
				
				//copy and convert fade duration argument 
				ixf.length = parseInt(arguments[2], 10) * 1000;
				
				//create fade resolution argument as 20 steps per transition
				ixf.resolution = parseInt(arguments[2], 10) * 20;
				
				//start the timer
				ixf.clock = setInterval('ixf.crossfade()', ixf.length/ixf.resolution);
			}
			
			//otherwise if opacity is not supported
			else
			{
				//just do the image swap
				ixf.obj.src = ixf.src;
			}
			
		}
	};


	//crossfade timer function
	ixf.crossfade = function()
	{
		//decrease the counter on a linear scale
		ixf.count -= (1 / ixf.resolution);
		
		//if the counter has reached the bottom
		if(ixf.count < (1 / ixf.resolution))
		{
			//clear the timer
			clearInterval(ixf.clock);
			ixf.clock = null;
			
			//reset the counter
			ixf.count = 1;
			
			//set the original image to the src of the new image
			ixf.obj.src = ixf.src;
		}
		
		//set new opacity value on both elements
		//using whatever method is supported
		switch(ixf.type)
		{
			case 'ie' :
				ixf.obj.filters.alpha.opacity = ixf.count * 100;
				ixf.newimg.filters.alpha.opacity = (1 - ixf.count) * 100;
				break;
				
			case 'khtml' :
				ixf.obj.style.KhtmlOpacity = ixf.count;
				ixf.newimg.style.KhtmlOpacity = (1 - ixf.count);
				break;
				
			case 'moz' : 
				//restrict max opacity to prevent a visual popping effect in firefox
				ixf.obj.style.MozOpacity = (ixf.count == 1 ? 0.9999999 : ixf.count);
				ixf.newimg.style.MozOpacity = (1 - ixf.count);
				break;
				
			default : 
				//restrict max opacity to prevent a visual popping effect in firefox
				ixf.obj.style.opacity = (ixf.count == 1 ? 0.9999999 : ixf.count);
				ixf.newimg.style.opacity = (1 - ixf.count);
		}
		
		//now that we've gone through one fade iteration 
		//we can show the image that's fading in
		ixf.newimg.style.visibility = 'visible';
		
		//keep new image in position with original image
		//in case text size changes mid transition or something
		ixf.newimg.style.left = ixf.getRealPosition(ixf.obj, 'x') + 'px';
		ixf.newimg.style.top = ixf.getRealPosition(ixf.obj, 'y') + 'px';
		
		//if the counter is at the top, which is just after the timer has finished
		if(ixf.count == 1)
		{
			//remove the duplicate image
			ixf.newimg.parentNode.removeChild(ixf.newimg);
		}
	};



	//get real position method
	ixf.getRealPosition = function()
	{
		this.pos = (arguments[1] == 'x') ? arguments[0].offsetLeft : arguments[0].offsetTop;
		this.tmp = arguments[0].offsetParent;
		while(this.tmp != null)
		{
			this.pos += (arguments[1] == 'x') ? this.tmp.offsetLeft : this.tmp.offsetTop;
			this.tmp = this.tmp.offsetParent;
		}
		
		return this.pos;
	};
}