var navifolder = "../images.books.two.state/"; 
    
    var books_travel_buttons_lo = new Array(books_travel_names.length);
    var books_travel_buttons_hi = new Array(books_travel_names.length);

	for (i = 0;  i < books_travel_names.length;  i++) {
		books_travel_buttons_lo[books_travel_names[i]] = new Image();
		books_travel_buttons_lo[books_travel_names[i]].src = navifolder + books_travel_names[i] + ".lo.png";
		books_travel_buttons_hi[books_travel_names[i]] = new Image();
		books_travel_buttons_hi[books_travel_names[i]].src = navifolder + books_travel_names[i] + ".hi.png";
	}
    
    function books_travel_button_hi(name) {
        document.images[name].src = books_travel_buttons_hi[name].src;
        return true;
    }
    function books_travel_button_lo(name) {
        document.images[name].src = books_travel_buttons_lo[name].src;
        return true;
    }