how to add html content using javascript code example

Example 1: how to add elements in javascript html

//adding 'p' tag to body

  var tag = document.createElement("p"); // <p></p>
  var text = document.createTextNode("TEST TEXT"); 
  tag.appendChild(text); // <p>TEST TEXT</p>
  var element = document.getElementsByTagName("body")[0];
  element.appendChild(tag); // <body> <p>TEST TEXT</p> </body>

Example 2: JavaScript append HTML

let app = document.querySelector('#app');
app.append('append() Text Demo');

console.log(app.textContent);