<html>
  <head>
    <title>zerocal</title>
    <style>
      body {
        font-family: monospace;
      }
      input,
      textarea,
      select {
        font-family: inherit;
      }
      label {
        color: #f81ce5;
      }
      #values {
        margin: 1em;
      }
    </style>
    <script>
      function updateUrl() {
        // Get the form
        let form = document.querySelector("#form");

        // If start is after end, set end to start
        let start = new Date(form.start.value);
