Edit in JSFiddle

$(document).ready(function () {
	var foo = $('li').get(0);
  var bar = $('#bar').get(0);
  
  $('#result1').text(foo.nodeName);
  $('#result2').text(bar.parentElement.nodeName);
});

<ul>
  <li id="foo">foo</li>
  <li id="bar">bar</li>
</ul>
<hr/>
<span id="result1"></span>
<span id="result2"></span>