Node.nodeType

The read-only Node.nodeType property is an integer that identifies what the node is. It distinguishes different kind of nodes from each other, such as elements, text and comments.

var type = node.nodeType;

Returns an integer which specifies the type of the node. Possible values are listed in Node type constants.

document.nodeType === Node.DOCUMENT_NODE; // true
document.doctype.nodeType === Node.DOCUMENT_TYPE_NODE; // true

document.createDocumentFragment().nodeType === Node.DOCUMENT_FRAGMENT_NODE; // true

var p = document.createElement("p");
p.textContent = "Once upon a time…";

p.nodeType === Node.ELEMENT_NODE; // true
p.firstChild.nodeType === Node.TEXT_NODE; // true

This example checks if the first node inside the document element is a comment, and displays a message if not.

var node = document.documentElement.firstChild;
if (node.nodeType !== Node.COMMENT_NODE) {
  console.warn("You should comment your code!");
}