Insert after/before

insertAfterBeforeHelper.js

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

// example
var newEl = document.createElement('div');
newEl.innerHTML = '<p>Hello World!</p>';

var ref = document.querySelector('div.before');

insertAfter(newEl, ref);


function insertBefore(el, referenceNode) {
    referenceNode.parentNode.insertBefore(el, referenceNode);
}

// example
var newEl = document.createElement('div');
newEl.innerHTML = '<p>Hello World!</p>';

var ref = document.querySelector('div.before');

insertBefore(newEl, ref);