Added vote button en/disabling, remaining vote count

scripts/poll.js

@@ -1,10 +1,39 @@
-window.addEventListener('DOMContentLoaded', (event) => {
+window.addEventListener('DOMContentLoaded', () => {
   displayLocalTimestamps();
+  for (const el of document.querySelectorAll('.option input[type=checkbox]')) {
+    el.onclick = updateVotesRemaining;
+  }
 });
 
 function displayLocalTimestamps() {
   for (const el of document.getElementsByTagName('time')) {
-    let dateObj = new Date(el.getAttribute('datetime'));
-    el.innerText = dateObj.toLocaleString();
+    const dateObj = new Date(el.getAttribute('datetime'));
+    const relDate = compareDateToToday(dateObj);
+    el.innerText = relDate === 0
+      ? `Today, ${dateObj.toLocaleTimeString()}`
+      : dateObj.toLocaleDateString();
   }
+}
+
+function compareDateToToday(date) {
+  const today = new Date();
+  if (today.getDate() === date.getDate()
+    && today.getMonth() === date.getMonth()
+    && date.getFullYear() === today.getFullYear()) {
+    return 0;
+  }
+  today.setHours(0, 0, 0, 0);
+  return today > date ? -1 : 1;
+}
+
+function updateVotesRemaining() {
+  const numChecked = document.querySelectorAll('.option input[type=checkbox]:checked').length;
+  const votesRemainingElement = document.querySelector('.votes-remaining');
+  const total = votesRemainingElement.dataset.maxVotes;
+  const remaining = Math.max(0, total - numChecked);
+  const plural = remaining === 1 ? '' : 's';
+  votesRemainingElement.innerText = `${remaining} Vote${plural} remaining`;
+  const voteButton = document.querySelector('button[name=submit_vote]');
+  const canVoteInitial = voteButton.dataset.canVote === 'true';
+  voteButton.disabled = !canVoteInitial || (total - numChecked) < 0 || numChecked === 0;
 }