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

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