if(navigator.appVersion.charAt(0) >= 3) {
 var img = new Array();
 img[0] = new Image();  img[0].src = "../images/b_company.gif";
 img[1] = new Image();  img[1].src = "../images/b_company_over.gif";
 img[2] = new Image();  img[2].src = "../images/b_shiryo.gif";
 img[3] = new Image();  img[3].src = "../images/b_shiryo_over.gif";
 img[4] = new Image();  img[4].src = "../images/b_policy.gif";
 img[5] = new Image();  img[5].src = "../images/b_policy_over.gif";
}
function change_image(nam,num) {
  if(navigator.appVersion.charAt(0) >= 3) {
    document.images[nam].src = img[num].src;
  }
}