Unable to get property 'addEventListener' of undefined or null reference. Unable to get property 'appendChild' of undefi

When I upload the code unable to create checkbox.

const form = document.getElementById('registrar'); const input = form.querySelector('input'); const ul = document.getElementById('invitedList');

function createLI(text){ const li = document.createElement('li'); li.textContent = text; const label = document.createElement('label'); label.textContent = 'Confirmed'; const checkbox = document.createElement('input'); checkbox.type = 'checkbox'; label.appendChild(checkbox); li.appendChild(label); const button = document.createElement('button'); button.textContent = 'remove'; li.appendChild(button); return li; };

form.addEventListener('submit', (e) => { e.preventDefault(); const text = input.value; input.value = ''; const li = createLI(text); ul.appendChild(li);
});

ul.addEventListener('change', (e) => { const checkbox = event.target; const checked = checkbox.checked; const listItem = checkbox.parentNode.parentNode;

if (checked){ listItem.className = 'responded'; } else { listItem.className = ''; } });

ul.addEventListener('click', (e) => { if (e.target.tagName === 'BUTTON'){ const li = e.target.parentNode; const ul = li.parentNode; ul.removeChild(li); } });