var	arrOff, arrOn, arrNames;		//arrays for images and image names
var bOkay;

bOkay= document.images;				//images OK?
arrOff = new Array();
arrOn = new Array();
arrNames = new Array();

//Called in the Onload event of the body tag

function preload()
{
	var iSlashIndex, iLastIndex;		//integers and indices
	var strName, strImagePath;			//image name and path
	var iCount, i, j;		
	
	if (bOkay)
	{
		iCount = document.images.length;
		j = 0;	
	
		for (i=0; i<iCount; i++)
		{
			strImagePath = document.images[i].src;
			strName = document.images[i].id;
			
			if (strName != "" && strImagePath.search("nav") > 0)
			{
				
				arrOff[strName] = new Image();
				arrOn[strName] = new Image();
				arrOff[strName].src = strImagePath;
				arrOn[strName].src = strImagePath.substr(0,strImagePath.length-4) + "_on.gif";
			}
		}
		
	}
}


function on(thisImage) 
{
	if (bOkay)
	{
		if (thisImage.id == null)
			return;
			
		strSrc = thisImage.src;
		if (strSrc.substring(strSrc.length-7,strSrc.length-4) == "_on")
			return;
		else 
			thisImage.src = arrOn[thisImage.id].src;
	}
}

function off(thisImage)
{
	if (bOkay)
	{
			if (thisImage.id == null)
				return;
				
			if (arrOff[thisImage.id] == null)
				return
				
			thisImage.src = arrOff[thisImage.id].src;
			
	}
}