/* 画像の先行読み込み */
if(document.images) {
 var imgs = new Array();
 imgs[0] = new Image();  imgs[0].src = "button/main_01.gif";
 imgs[1] = new Image();  imgs[1].src = "button/main_02.gif";
 imgs[2] = new Image();  imgs[2].src = "button/sys_01.gif";
 imgs[3] = new Image();  imgs[3].src = "button/sys_02.gif";
 imgs[4] = new Image();  imgs[4].src = "button/sche_01.gif";
 imgs[5] = new Image();  imgs[5].src = "button/sche_02.gif";
 imgs[6] = new Image();  imgs[6].src = "button/lineup_01.gif";
 imgs[7] = new Image();  imgs[7].src = "button/lineup_02.gif";
 imgs[8] = new Image();  imgs[8].src = "button/wait_01.gif";
 imgs[9] = new Image();  imgs[9].src = "button/wait_02.gif";
 imgs[10] = new Image();  imgs[10].src = "button/process_01.gif";
 imgs[11] = new Image();  imgs[11].src = "button/process_02.gif";
 imgs[12] = new Image();  imgs[12].src = "button/reserv_01.gif";
 imgs[13] = new Image();  imgs[13].src = "button/reserv_02.gif";
 imgs[14] = new Image();  imgs[14].src = "button/magazine_01.gif";
 imgs[15] = new Image();  imgs[15].src = "button/magazine_02.gif";
 imgs[16] = new Image();  imgs[16].src = "button/job_01.gif";
 imgs[17] = new Image();  imgs[17].src = "button/job_02.gif";
 imgs[18] = new Image();  imgs[18].src = "button/lec_01.gif";
 imgs[19] = new Image();  imgs[19].src = "button/lec_02.gif";
 imgs[20] = new Image();  imgs[20].src = "button/an_01.gif";
 imgs[21] = new Image();  imgs[21].src = "button/an_02.gif";
 imgs[22] = new Image();  imgs[22].src = "button/pri_01.gif";
 imgs[23] = new Image();  imgs[23].src = "button/pri_02.gif";
 imgs[24] = new Image();  imgs[24].src = "button/af_01.gif";
 imgs[25] = new Image();  imgs[25].src = "button/af_02.gif";
 imgs[26] = new Image();  imgs[26].src = "button/rank_01.gif";
 imgs[27] = new Image();  imgs[27].src = "button/rank_02.gif";
 imgs[28] = new Image();  imgs[28].src = "button/future_01.gif";
 imgs[29] = new Image();  imgs[29].src = "button/future_02.gif";
 imgs[30] = new Image();  imgs[30].src = "button/raiten_01.gif";
 imgs[31] = new Image();  imgs[31].src = "button/raiten_02.gif";
}

function chgimg(id, imgname) {
 if(document.images) {
  if(imgs[imgname]) {
    document.images[id].src = imgs[imgname].src;
  }
  else {
    document.images[id].src = imgname;
  }
 }
}