//¸ÞÀθ޴º¿¡ °ü·ÃµÈ Åܸ޴º
 var prevLayer = new Array();
 prevLayer[0] = "layer_1";
 prevLayer[1] = "layer_3";
 prevLayer[2] = "layer_7";


 var prevImg  = new Array();
 prevImg[0]  = "img_1";
 prevImg[1]  = "img_3";
 prevImg[2]  = "img_7";

 
 function viewLayer(nowLayer,no)
 {
  document.all[prevLayer[no]].style.display = "none";
  document.all[nowLayer].style.display = "";
  prevLayer[no] = nowLayer;
 }

 function changeImg(nowImg,no)
 {
  if ( nowImg != prevImg[no] )
  {
   prevImgSrc = document.all[prevImg[no]].src.replace("_on.gif",".gif");
   nowImgSrc = document.all[nowImg].src.replace("_off.gif",".gif");

   document.all[prevImg[no]].src = prevImgSrc.replace(".gif","_off.gif");
   document.all[nowImg].src = nowImgSrc.replace(".gif","_on.gif");
   prevImg[no] = nowImg;
  }
 }