JS HTML
(quick guide & examples)
TARGET ELEMENT <p id="para">FOO</p>
GET HTML ELEMENT var p = document.getElementById("para");";
REPLACE "FOO" WITH "DOO" p.innerHTML = "DOO";
TO APPEND p.innerHTML += "<strong>ZOO</strong>";
TARGET ELEMENT <p id="para">FOO</p>
CREATE NEW ELEMENT let s = document.createElement("strong"); s.innerHTML = "ZOO";
GET TARGET var p = document.getElementById("para");
APPEND NEW ELEMENT p.appendChild(s);