function SwapLanguage() {
  var i, url, s=document.location.href;

  i = s.indexOf("/en/");
  if (i > -1) {
    url=s.substring(0,i+1) + "jp" + s.substring(i+3);
  } else {
    i = s.indexOf("/jp/");
    url=s.substring(0,i+1) + "en" + s.substring(i+3);
  }
  
  document.location.href = url;
}