if(document.images) {
  
	var burron = new Image();  
	var burroff = new Image();
	var hamiltonon = new Image();
	var hamiltonoff = new Image();
	var ruleson = new Image();
	var rulesoff = new Image();
	var duelon = new Image();
	var dueloff = new Image();
	
	burroff.src = "images/sf_burr_off.gif"
	burron.src = "images/sf_burr_on.gif"
	hamiltonoff.src = "images/sf_hamilton_off.gif"
	hamiltonon.src = "images/sf_hamilton_on.gif"
	rulesoff.src = "images/sf_code_off.gif"
	ruleson.src = "images/sf_code_on.gif"
	dueloff.src = "images/sf_duel_off.gif"
	duelon.src = "images/sf_duel_on.gif"
}


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

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