Node.compareDocumentPosition()

The Node.compareDocumentPosition() method reports the position of its argument node relative to the node on which it is called.

Syntax

node.compareDocumentPosition(otherNode)

Parameters

otherNode: The Node for which position should be reported, relative to node.

Return value

An integer value representing otherNode's position relative to node as a bitmask combining the following constant properties of Node:

Constant	Value	Description
`Node.DOCUMENT_POSITION_DISCONNECTED`	1	`otherNode` and `node` are in different documents or different trees in the same document
`Node.DOCUMENT_POSITION_PRECEDING`	2	`otherNode` precedes `node` in either a pre-order depth-first traversal of a tree containing both (e.g., as an ancestor or previous sibling or a descendant of a previous sibling or previous sibling of an ancestor) or (if they are disconnected) in an arbitrary but consistent ordering
`Node.DOCUMENT_POSITION_FOLLOWING`	4	`otherNode` follows `node` in either a pre-order depth-first traversal of a tree containing both (e.g., as a descendant or following sibling or a descendant of a following sibling or following sibling of an ancestor) or (if they are disconnected) in an arbitrary but consistent ordering
`Node.DOCUMENT_POSITION_CONTAINS`	8	`otherNode` is an ancestor of `node`
`Node.DOCUMENT_POSITION_CONTAINED_BY`	16	`otherNode` is a descendant of `node`
`Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC`	32	the result relies upon arbitrary and/or implementation-specific behavior and is not guaranteed to be portable

More than one bit is set if multiple scenarios apply. For example, if otherNode is located earlier in the document and contains the node on which compareDocumentPosition() was called, then both the DOCUMENT_POSITION_CONTAINS and DOCUMENT_POSITION_PRECEDING bits would be set, producing a value of 10 (0x0A).

Example

const head = document.head;
const body = document.body;

if (head.compareDocumentPosition(body) & Node.DOCUMENT_POSITION_FOLLOWING) {
  console.log('Well-formed document');
} else {
  console.error('<head> is not before <body>');
}

Note: Because the result returned by compareDocumentPosition() is a bitmask, the bitwise AND operator must be used for meaningful results.

Specifications

Specification
DOM Standard (DOM) # ref-for-dom-node-comparedocumentposition①

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`compareDocumentPosition`	1	12	9	9 Only supports `contains` for elements	≤12.1	4	≤37	18	9	≤12.1	3.2	1.0