function imgOn(imgName) 
{	
	if (document.images)
	{
		document.images[imgName].src = eval(imgName + "on.src");
	}
}

// Function to 'deactivate' images.

function imgOff(imgName) 
{ 
	if (document.images) 
	{
		document.images[imgName].src = eval(imgName + "off.src");
	}
}

if (document.images) 
{            
	backarrow01on = new Image();
	backarrow01on.src = "/images-guidebook/backarro_0.gif";

	backarrow01off = new Image();
	backarrow01off.src = "/images-guidebook/backarro_1.gif";
	
	nextarrow01on = new Image();
	nextarrow01on.src = "/images-guidebook/nextarro_0.gif";

	nextarrow01off = new Image();
	nextarrow01off.src = "/images-guidebook/nextarro_1.gif";
}