var Training_On = new Image();
	Training_On.src = "images/training_on.gif";
	var Training_Off = new Image();
	Training_Off.src = "images/training.gif";
	
	var Calibration_On = new Image();
	Calibration_On.src = "images/calibration_on.gif";
	var Calibration_Off = new Image();
	Calibration_Off.src = "images/calibration.gif";
	
	var Rentals_On = new Image();
	Rentals_On.src = "images/rentals_on.gif";
	var Rentals_Off = new Image();
	Rentals_Off.src = "images/rentals.gif";
	
	var Checkout_On = new Image();
	Checkout_On.src = "images/header_checkout_on.gif";
	var Checkout_Off = new Image();
	Checkout_Off.src = "images/header_checkout.gif";
	
	var Cart_On = new Image();
	Cart_On.src = "images/header_cart_on.gif";
	var Cart_Off = new Image();
	Cart_Off.src = "images/header_cart.gif";
	
	var Account_On = new Image();
	Account_On.src = "images/header_account_on.gif";
	var Account_Off = new Image();
	Account_Off.src = "images/header_account.gif";
	
	
	
function rollOn(btn){
	if(btn == "training"){
		document.images["btnTraining"].src = Training_On.src;
	}else if(btn == "calibration"){
		document.images["btnCalibration"].src = Calibration_On.src;
	}else if(btn == "rentals"){
		document.images["btnRentals"].src = Rentals_On.src;	
	}else if(btn == "checkout"){
		document.images["btnCheckout"].src = Checkout_On.src;	
	}else if(btn == "cart"){
		document.images["btnCart"].src = Cart_On.src;	
	}else if(btn == "account"){
		document.images["btnAccount"].src = Account_On.src;	
	}
	
}

function rollOff(btn){
	if(btn == "training"){
		document.images["btnTraining"].src = Training_Off.src;
	}else if(btn == "calibration"){
		document.images["btnCalibration"].src = Calibration_Off.src;
	}else if(btn == "rentals"){
		document.images["btnRentals"].src = Rentals_Off.src;
	}else if(btn == "checkout"){
		document.images["btnCheckout"].src = Checkout_Off.src;
	}else if(btn == "cart"){
		document.images["btnCart"].src = Cart_Off.src;
	}else if(btn == "account"){
		document.images["btnAccount"].src = Account_Off.src;
	}
}