获取节点公共的父节点

get_common_ancestor.js

    function getCommonAncestor(nodes) {
        if (!nodes || !nodes.length) {
            return null;
        }
        else if (nodes.length == 1) {
            return nodes[0].parentNode;
        } else {
            var p = nodes[0],
                pass = 0;
            while (!pass && p != document.body) {
                p = p.parentNode;
                pass = 1;
                for (var i = 1; i < nodes.length; i++) {
                    if (!DOM.contains(p, nodes[i])) {
                        pass = 0;
                        break;
                    }
                }
            }
            return p;
        }
    }