function preLoadImage(imageURL) {
		image = new Image();
		image.src = imageURL;
		return image;
}

function changeButtonImage(buttonName,sourceImage) {
		document [buttonName].src = sourceImage.src;
		return true;
}

button1 = preLoadImage("images/tab1.gif");
button1a = preLoadImage("images/tab1a.gif");
button2 = preLoadImage("images/tab2.gif");
button2a = preLoadImage("images/tab2a.gif");
button3 = preLoadImage("images/tab3.gif");
button3a = preLoadImage("images/tab3a.gif");
button4 = preLoadImage("images/tab4.gif");
button4a = preLoadImage("images/tab4a.gif");
button5 = preLoadImage("images/tab5.gif");
button5a = preLoadImage("images/tab5a.gif");
button6 = preLoadImage("images/menu1.gif");
button6a = preLoadImage("images/menu1a.gif");
button7 = preLoadImage("images/menu2.gif");
button7a = preLoadImage("images/menu2a.gif");
button8 = preLoadImage("images/menu3.gif");
button8a = preLoadImage("images/menu3a.gif");
button9 = preLoadImage("images/menu4.gif");
button9a = preLoadImage("images/menu4a.gif");
button0 = preLoadImage("images/menu5.gif");
button0a = preLoadImage("images/menu5a.gif");