how to insert text using javascript code example

Example: how to add text in javascript

<div id="mass">
<p id="ph1">This is a paragraph.</p>
<p id="ph2">This is another paragraph.</p>
</div>

<script>
var head = document.createElement("h1");
var node = document.createTextNode("New Heading.");
head.appendChild(node);

var ele = document.getElementById("mass");
var child = document.getElementById("ph1");
ele.insertBefore(head,child);
//ele.append(head,child);

Output : 
New Heading.
This is a paragraph.
This is another paragraph.