function display_over_img(img_num) {
	// This function is called when the OnMouseOver event takes place.  The function uses the value
	// of img_num to determine which button the cursor has just moused over.  It then displays the
	// over version of that button.
	
	switch (img_num) {
		
		case home_img_num: 
				home.src = over_images[img_num];
				break;
			
		case contest_img_num: 
				contest.src = over_images[img_num];
				break;
		
		case guestbook_img_num: 
				guestbook.src = over_images[img_num];
				break;
		
		case athome_img_num: 
				athome.src = over_images[img_num];
				break;
	}
}



function display_out_img(img_num) {
	// This function is called when the OnMouseOut event takes place.  The function uses the value
	// of img_num to determine which button the cursor has just been removed from.  It then displays the
	// out version of that button.
	
	switch (img_num) {
		
		case home_img_num: 
				home.src = out_images[img_num];
				break;
		
		case contest_img_num: 
				contest.src = out_images[img_num];
				break;

		case guestbook_img_num: 
				guestbook.src = out_images[img_num];
				break;
		
		case athome_img_num: 
				athome.src = out_images[img_num];
				break;
	}
}