function tgmm() {
  var x = document.getElementById("myTopnav");
  if (x.className === "topnav") {
    x.className += " responsive";
  } else {
    x.className = "topnav";
  }
  var mmb = document.getElementById("mmb");
  if (mmb.className === "fa fa-bars") {
    mmb.className += " fa fa-close";
  } else {
    mmb.className = "fa fa-bars";
  }
}