ParentNode.append()

The ParentNode.append() method inserts a set of Node objects or DOMString objects after the last child of the ParentNode. DOMString objects are inserted as equivalent Text nodes.

Differences from Node.appendChild():

• ParentNode.append() allows you to also append DOMString objects, whereas Node.appendChild() only accepts Node objects.
• ParentNode.append() has no return value, whereas Node.appendChild() returns the appended Node object.
• ParentNode.append() can append several nodes and strings, whereas Node.appendChild() can only append one node.

// [Throws, Unscopable]
ParentNode.append(...nodesOrDOMStrings) // returns undefined

nodesOrDOMStrings

A set of Node or DOMString objects to insert.

• HierarchyRequestError: Node cannot be inserted at the specified point in the hierarchy.

let parent = document.createElement("div")
let p = document.createElement("p")
parent.append(p)

console.log(parent.childNodes) // NodeList [ <p> ]

let parent = document.createElement("div")
parent.append("Some text")

console.log(parent.textContent) // "Some text"

let parent = document.createElement("div")
let p = document.createElement("p")
parent.append("Some text", p)

console.log(parent.childNodes) // NodeList [ #text "Some text", <p> ]

The append() method is not scoped into the with statement. See Symbol.unscopables for more information.

let parent = document.createElement("div")

with(parent) {
  append("foo")
}
// ReferenceError: append is not defined 

You can polyfill the append() method in Internet Explorer 9 and higher with the following code:

// Source: https://github.com/jserz/js_piece/blob/master/DOM/ParentNode/append()/append().md
(function (arr) {
  arr.forEach(function (item) {
    if (item.hasOwnProperty('append')) {
      return;
    }
    Object.defineProperty(item, 'append', {
      configurable: true,
      enumerable: true,
      writable: true,
      value: function append() {
        var argArr = Array.prototype.slice.call(arguments),
          docFrag = document.createDocumentFragment();

        argArr.forEach(function (argItem) {
          var isNode = argItem instanceof Node;
          docFrag.appendChild(isNode ? argItem : document.createTextNode(String(argItem)));
        });

        this.appendChild(docFrag);
      }
    });
  });
})([Element.prototype, Document.prototype, DocumentFragment.prototype]);

• ParentNode and ChildNode
• ParentNode.prepend()
• Node.appendChild()
• ChildNode.after()
• Element.insertAdjacentElement()
• NodeList