function preloadImage() {

   image_list = new Array("art", "dance", "film", "music", "radio", "theater", 
       "etc");
   var load_it = new Array();
   var load_alt = new Array();
   for (var i=0; i<image_list.length; i++) {
       load_it[i] = new Image();
       load_it[i].src = "/images/" + image_list[i] + "button.gif";
       load_alt[i] = new Image();
       load_alt[i].src = "/images/" + image_list[i] + "button-a.gif";
   }

}


function changeButton(button_number) {

   var button_name = document.images[button_number].src;
   var new_button = button_name.substring(0,button_name.length - 4) +
       "-a.gif";
   document.images[button_number].src = new_button;
   
   var active_button = document.images[10].src;
   active_button = active_button.substring(0,active_button.length - 6) +
       ".gif";
   document.images[10].src = active_button;

}

function changeBack(button_number) {

   var button_name = document.images[button_number].src;
   var new_button = button_name.substring(0,button_name.length - 6) +
       ".gif";
   document.images[button_number].src = new_button;

   var active_button = document.images[10].src;
   active_button = active_button.substring(0,active_button.length - 4) +
       "-a.gif";
   document.images[10].src = active_button;
   
}