Answers for "append after elemnt"

jquery append after

<div class="container">
  <h2>Greetings</h2>
  <div class="inner">Hello</div>
  <div class="inner">Goodbye</div>
</div>
<script>$( "<p>Test</p>" ).insertAfter( ".inner" );</script>

append sibling javascript after first child

function insertAfter(newNode, referenceNode) {
    referenceNode.parentNode.insertBefore(newNode, referenceNode.nextSibling);
}