if (document.images) {
img = new Image(); img.src = "image/menu_01_1.gif";
img = new Image(); img.src = "image/menu_01_2.gif";
img = new Image(); img.src = "image/menu_02_1.gif";
img = new Image(); img.src = "image/menu_02_2.gif";
img = new Image(); img.src = "image/menu_03_1.gif";
img = new Image(); img.src = "image/menu_03_2.gif";
}