Summary

Compares the position of the current node against another node in any other document.

Syntax

node.compareDocumentPosition( otherNode ) 

• node is the node that's being compared.
• otherNode is the node that's being compared against.

The return value is computed as the relationship that otherNode has with node.

Notes

The return value is a bitmask with the following values:

DOCUMENT_POSITION_DISCONNECTED = 1;
DOCUMENT_POSITION_PRECEDING    = 2;
DOCUMENT_POSITION_FOLLOWING    = 4;
DOCUMENT_POSITION_CONTAINS     = 8;
DOCUMENT_POSITION_CONTAINED_BY = 16;

Example

var head = document.getElementsByTagName('head').item(0);
var result = head.compareDocumentPosition(document.body);
// result = head.DOCUMENT_POSITION_FOLLOWING

Specification

DOM Level 3: compareDocumentPosition