javascript insert a new element on document code example
Example 1: javascript append to paragraph
var parElement = document.getElementById("myPar");
var textToAdd = document.createTextNode("Text to be added");
parElement.appendChild(textToAdd);
<p id="myPar"></p>
Example 2: how to add elements in javascript html
var tag = document.createElement("p");
var text = document.createTextNode("TEST TEXT");
tag.appendChild(text);
var element = document.getElementsByTagName("body")[0];
element.appendChild(tag);