how to append or add new html element in javascript code example

Example 1: add element to body javascript

var elem = document.createElement('div');
elem.style.cssText = 'position:absolute;width:100%;height:100%;opacity:0.3;z-index:100;background:#000';
document.body.appendChild(elem);

Example 2: javascript add div

<div id="new">
<p id="p1">Tutorix</p>
<p id="p2">Tutorialspoint</p>
</div>
<script>
   var tag = document.createElement("p");
   var text = document.createTextNode("Tutorix is the best e-learning platform");
   tag.appendChild(text);
   var element = document.getElementById("new");
   element.appendChild(tag);
</script>