function menuTurnOn(elementImage) { 	
	// now reset source with "on" version of image
	elementImage.src = 
		parseImagePath(elementImage) + parseImageName(elementImage) + "_on.gif";
}

function menuTurnOff(elementImage) { 
	// now reset source with "on" version of image
	elementImage.src = 
		parseImagePath(elementImage) + parseImageName(elementImage) + "_off.gif";	
}

function parseImageName(elementImage) { 
	return (
		elementImage.src.match(/[a-z]+_(off|on)\.gif/)[0].match(/[a-z]+/)[0]
	);
}

function parseImagePath(elementImage) { 
	return elementImage.src.match(/.+\//)[0];	
}