document.addEventListener("DOMContentLoaded", function() {
  console.log(date);
  date = date === "{$date}" ? moment().format("Y-MM-DD") : date;
  console.log(date);
  tz = tz === "{$tz}" ? "UTC" : tz;
  tz = tz === "EST" ? "America/New_York" : tz;
  tz = tz === "EDT" ? "America/New_York" : tz;
  tz = tz === "BST" ? "Europe/London" : tz;

  given_time = moment.tz(date + " " + time, tz);
  tz = given_time.format("z");

  text_before = text_before === "{$text_before}" ? "${time} ${tz} is " : 
text_before;
  text_after = text_after === "{$text_after}" ? "." : text_after;
  // eval is used here to convert text strings to template literals
  // variables of the form ${var} will be parsed
  text_before = eval('`' + text_before + '`');
  text_after = eval('`' + text_after + '`');

  user_tz = Intl.DateTimeFormat().resolvedOptions().timeZone;
  converted_time = given_time.tz(user_tz);
  converted_time_tz = converted_time.format("HH:mm z");

  console.log(given_time);
  console.log(converted_time);

  document.getElementById("text_before").textContent = text_before;
  document.getElementById("text_converted").textContent = converted_time_tz;
  document.getElementById("text_after").textContent = text_after;

  if (converted_time.format("z") === tz) {
    // e.g. displaying an EST time to an EST user - that's pointless!
    document.documentElement.style.display = 'none';
  }
});