In line 28, where there is "ul.appendChild(li); , why are there no quotation marks around the li element? Thank you!

Hi Lisa,

On line 28 you're passing in li as a variable that you've defined on the previous 2 lines of code:

// make a list item element and store it in the variable li
let li = document.createElement('li');
// insert the input value in to element in the li variable
li.textContent = addItemInput.value;

We can name this variable anything we like as long as it's consistent. I could rewrite this block with something like newListItem instead and it works just the same:

addItemButton.addEventListener('click', () => {
  let ul = document.getElementsByTagName('ul')[0];
  let newListItem = document.createElement('li');
  newListItem.textContent = addItemInput.value;
  ul.appendChild(newListItem);
  addItemInput.value = '';
});

To dig in to it deeper, the querySelector() method accepts a string as its parameter -- hence the quotation marks. The appendChild() method accepts a node object as a parameter instead, which we created with document.createElement('li'), stored in a variable, and then passed in to it with the variable we defined.

To check this yourself take a look the documentation on these 3 methods and scroll down to the 'parameters' area:
querySelector()
createElement()
appendChild()

I hope this helps! If you have any questions let me know and I'll do my best to clear things up.