// イメージ入れ替え＆プリロード

img = new Array("images/lift2007on.jpg","images/lift2007off.jpg","images/nabe2007on.jpg","images/nabe2007off.jpg","images/sp2007on.jpg","images/sp2007off.jpg");
bfImg = new Array();
for(i=0; i<img.length; i++) {
  bfImg[i] = new Image();
  bfImg[i].src = img[i];
}