if(navigator.appVersion.charAt(0) >= "3"){
  img = new Array();
  img[1] = new Image; img[1].src = "im01.jpg";
  img[2] = new Image; img[2].src = "im02.jpg";
  img[3] = new Image; img[3].src = "im03.jpg";
  img[4] = new Image; img[4].src = "im04.jpg";
  img[5] = new Image; img[5].src = "im05.jpg";
  img[6] = new Image; img[6].src = "im06.jpg";
  img[7] = new Image; img[7].src = "im07.jpg";
  img[8] = new Image; img[8].src = "im08.jpg";
  img[9] = new Image; img[9].src = "im09.jpg";
  img[10] = new Image; img[10].src = "im10.jpg";
  img[11] = new Image; img[11].src = "im11.jpg";
  img[12] = new Image; img[12].src = "im12.jpg";
}
function chg_img(a){  //aは上の配列に対応
  if(navigator.appVersion.charAt(0) >= "3"){
    document.images["img1"].src=img[a].src;
  }
}