-firstChild firstElementChild
var oFirst = oUl.firstChild || oUl.firstElementChild;
-lastChild lastElementChild
var oLast = oUl.lastChild || oUl.lastElementChild;
-nextSibling nextElementSibling;
var oNext = oUl.nextSibling || oUl.nextElementSibling;
-previousSibling previousElementSibling
var oPre = oUl.previousSibling || oUl.previousElementSibling;