// For Tag name like h1,h2, etc... //getElementById('tagname') // node-list = array like object // index, length property but not array method const list_manga = document.getElementsByTagName('li'); console.log(list_manga); //here will result node-list like [li,li,li] use index // change naruto be capitalize list_manga[1].style.textTransform = 'capitalize'; // if use forEach copy obj use spread operator // if not will not work const newListManga = [...list_manga]; newListManga.forEach(function (items) { items.style.textTransform = 'uppercase'; items.style.padding = '1.25rem 0rem'; }); // add background on the last index be blue color newListManga[newListManga.length - 1].style.background = 'blue';