document.getElementById("p").textContent += " This is the text from javascript."; <p id ="p">This is the text from HTML.</p>
let arr = ["g", "o", "o", "g", "L", "e"; let ul = document.getElementById("id_ul"); let i =0; arr.map(arr=>{ var li = document.createElement("li"); ul.appendChild(li); li.innerHTML = arr[i]; })