Node

Members shared by every node — the document, elements, text, comments, and fragments alike: traversal, tree mutation, character data, and metadata. Element-only navigation (children, firstElementChild, …) is on the Element page. All mutators are guarded and throw NoModificationAllowedError on a read-only document.

Traversal

All-kinds navigation (text and comment nodes are included). Each returns a handle or null.

Accessor Value
parentNode The parent, or null.
parentElement The parent only if it is an element, else null.
firstChild / lastChild First / last child of any kind, or null.
previousSibling / nextSibling Adjacent sibling of any kind, or null.
childNodes A static NodeList of all child kinds.
ownerDocument The owning document — null when called on the document itself.

hasChildNodes

hasChildNodes() → boolean.

if (node.hasChildNodes()) {
  for (const child of node.childNodes) { /* text and elements */ }
}

Metadata

Accessor Value
nodeType The numeric type code — compare against the Node constants.
nodeName Element = uppercased tag; otherwise #text, #comment, #document, #document-fragment, the doctype name, or a PI target. 
if (node.nodeType === Node.ELEMENT_NODE) { /* it's an element */ }

Character data

textContent

Get concatenates all descendant text (a comment yields its own data). Set replaces every child with a single text node — an empty string leaves no children. Available on every node; guarded.

cell.textContent = "42";
const words = article.textContent.split(/\s+/).length;

data / length

data (get/set) and length (get) are CharacterData members, so they apply to text and comment nodes: data is the character payload, length its Unicode character count. On a node of any other interface they are out of scope, so element.data and element.length are undefined. Setting data is guarded.

const c = document.createComment("draft");
c.data;          // "draft"
c.length;        // 5
c.data = "final";

Tree mutation

A node from another document is adopted (deep-copied); a DocumentFragment argument moves its children (leaving the fragment empty).

appendChild

appendChild(child) → the appended child. Appending a node to its own descendant or itself throws HierarchyRequestError.

list.appendChild(document.createElement("li"));

insertBefore

insertBefore(node, reference) → the inserted node. A null/omitted reference behaves like appendChild; otherwise reference must be a current child, else NotFoundError.

list.insertBefore(newItem, list.firstChild);   // insert at the top

removeChild

removeChild(child) → the removed child (which stays live with parentNode === null). child must be a child, else NotFoundError.

list.removeChild(list.lastChild);

replaceChild

replaceChild(newNode, oldNode) → oldNode. oldNode must be a child, else NotFoundError.

list.replaceChild(document.createElement("li"), staleItem);

cloneNode

cloneNode(deep?) → a detached clone (deep defaults to false). Rejected on a read-only document — the clone would allocate into the read-only arena.

const copy = template.cloneNode(true);

contains

contains(other) → boolean; false across documents.

if (main.contains(node)) { /* node is inside <main> */ }

Node constants

The Node global exposes the standard node-type constants, for comparison against nodeType:

Node.ELEMENT_NODE (1) · Node.TEXT_NODE (3) · Node.COMMENT_NODE (8) · Node.DOCUMENT_NODE (9) · Node.DOCUMENT_TYPE_NODE (10) · Node.DOCUMENT_FRAGMENT_NODE (11)

See also