if (document.images) 
	{	var n;
		imgs = new Array(2);
		for (n=0; n < imgs.length; n++) imgs[n] = new Image();
		imgs[0].src = "graphics/book_small.gif";
		imgs[1].src = "graphics/book_small01.gif";
	}
function turnOn(imgName) 
	{  	if (document.images)
		{	document[imgName].src="graphics/book_small01.gif";	}
	}
function turnOff(imgName)
	{  	if (document.images)
		{	document[imgName].src="graphics/book_small.gif";	}
	}