function showPassword(id) {
  var x = document.getElementById(id);
  if (x.type === "password") {
    x.type = "text";
  } else {
    x.type = "password";
  }
}

// https://www.w3schools.com/howto/howto_js_collapsible.asp
var coll = document.getElementsByClassName("collapsible");
var i;

for (i = 0; i < coll.length; i++) {
  coll[i].addEventListener("click", function() {
    this.classList.toggle("active");
    var content = this.nextElementSibling;
    if (content.style.display === "block") {
      content.style.display = "none";
    } else {
      content.style.display = "block";
    }
  });
}