var X = document.getElementById("intro");
var x = document.getElementsByTagName("p");
var x = document.getElementsByClassName("intro");
var x = document.querySelectorAll("p.intro");

element.innerHTML = new html content     // Exam:- object.innerHTML/.innerText/.textContent = "<p>Dog</p>";
element.attribute = new value            // Exam:- object.src = "landscape.jpg";
element.style.property=newstyle          // Exam:- object.style.color="blue";
element.setAttribute(attribute, value)   // Exam:- object.setAttribute("style", "background-color: red;");
element.removeAttribute(attributename)   // Exam:- object.removeAttribute("href");