function openCity(evt, cityName) {
  var i, x, tablinks;
  x = document.getElementsByClassName("city");
  for (i = 0; i < x.length; i++) {
     x[i].style.display = "none";
  }
  tablinks = document.getElementsByClassName("tablink");
  for (i = 0; i < x.length; i++) {
      tablinks[i].className = tablinks[i].className.replace(" w3-red", ""); 
  }
  document.getElementById(cityName).style.display = "block";
  evt.currentTarget.className += " w3-red";
}

function openCity2(evt, cityName) {
  var i, x, tablinks;

  x = document.getElementsByClassName("gold");
  for (i = 0; i < x.length; i++) {
     x[i].style.display = "none";
  }
  tablinks = document.getElementsByClassName("tablink");
  for (i = 0; i < x.length; i++) {
     tablinks[i].className = tablinks[i].className.replace(" w3-border-green", "");
  }
  document.getElementById(cityName).style.display = "block";

  evt.currentTarget.firstElementChild.className += " w3-border-green";
}
