function translateUrl(url) {
  // data
  var endEnUrl = '.html';
  var endJpUrl = '_jp.html';
  // translation
  var buffer = ''+url;
  if (buffer.indexOf(endJpUrl) >= 0) {
    return (buffer.substring(0,buffer.indexOf(endJpUrl)) + endEnUrl + buffer.substring(buffer.indexOf(endJpUrl)+endJpUrl.length,buffer.length));
  }
  return (buffer.substring(0,buffer.indexOf(endEnUrl)) + endJpUrl + buffer.substring(buffer.indexOf(endEnUrl)+endEnUrl.length,buffer.length));
}


function validate_guestbook(form){
  msg = "You forgot to fill in some fields :\n"
  if(form.message!=null&&form.message.value.length<1){
    msg = msg+" - please write a message \n"
  }
  if(form.name!=null&&form.name.value.length<1){
    msg = msg+" - please write your name \n"
  }
  if(msg.length<50){
    return true
  }
  else{
    alert(msg)
    return false
  }
}