//image array

var swapimage; swapimage = new Array;

//preload function

function preload() {
var N = preload.arguments[0];
swapimage[N] = new Image();
swapimage[N][0] = new Image();
swapimage[N][0].src = preload.arguments[1];
swapimage[N][1] = new Image();
swapimage[N][1].src = preload.arguments[2];
}

//rollover function

function changeimage() {
var ID = changeimage.arguments[0];
var N = changeimage.arguments[1];
document.images[ID].src = swapimage[ID][N].src;
}

//preload images
preload('menu_01', '../image/menu_01a.gif', '../image/menu_01b.gif');
preload('menu_02', '../image/menu_02a.gif', '../image/menu_02b.gif');
preload('menu_03', '../image/menu_03a.gif', '../image/menu_03b.gif');
preload('menu_04', '../image/menu_04a.gif', '../image/menu_04b.gif');
preload('menu_05', '../image/menu_05a.gif', '../image/menu_05b.gif');
preload('menu_06', '../image/menu_06a.gif', '../image/menu_06b.gif');
preload('menu_07', '../image/menu_07a.gif', '../image/menu_07b.gif');
preload('menu_08', '../image/menu_08a.gif', '../image/menu_08b.gif');
preload('english', '../image/head_english_a.gif', '../image/head_english_b.gif');
preload('japanese', '../image/head_japanese_a.gif', '../image/head_japanese_b.gif');