`jQuery#commonAncestor()` and `getCommonAncestor(node /*, node2, node3, ... nodeN */)`

README.md

jQuery.commonAncestor plugin

Usage

$(nodes, to, find, common, ancestor, of).commonAncestor()

Credits

See also: test case, StackExchange origin

jquery.commonAncestor.js

function getCommonAncestor(node /*, node2, node3, ... nodeN */) {
  if (!node || node.nodeType !== 1)
    throw new Error('getCommonAncestor: need at least one Node');

  var nodes   = [].slice.call(arguments, 1)
    , method  = 'compareDocumentPosition'
    , bitmask = 0x0010;
  if ('contains' in node) {
    method = 'contains';
    bitmask = 1;
  }

  rocking:
  while ((node = node && node.parentNode)) {
    for (var i = nodes.length; i--;) {
      if ((node[method](nodes[i]) & bitmask) !== bitmask)
        continue rocking;
    }
    return node;
  }

  return undefined;
}

jQuery.fn.commonAncestor = function() {
  return $(getCommonAncestor.apply(null, this));
};