题解 | #dom 节点查找#

function commonParentNode(oNode1, oNode2) {
    if ( oNode1 === oNode2 ) return '';
    while (true) {
        if (oNode1.contains(oNode2) || oNode1 === oNode2)
            return oNode1
        oNode1 = oNode1.parentNode
    }
}