if the datetime field isn't there, don't try to set it

app/static/time.js

@@ -1,7 +1,7 @@
 document.addEventListener('DOMContentLoaded', () => {
-var currentTime = new Date();
-const $myDatetimeField =  document.querySelector('#butterbox_date')
+    const $myDatetimeField = document.querySelector('#butterbox_date');
+    if (!$myDatetimeField) return;
+    const currentTime = new Date();
     console.log(currentTime.toISOString().substring(0, 19));
     $myDatetimeField.value = currentTime.toISOString().substring(0, 19) + 'Z';
-
 });