parseHtml.js

 var doc = document, win = window;
 var frag;
  function parseHTML(str) {
    if (!frag) {
      frag = doc.implementation.createHTMLDocument(null);
      var base = frag.createElement("base");
      base.href = doc.location.href;
      frag.head.appendChild(base);
    }

    frag.body.innerHTML = str;

    return frag.body.childNodes;
  }

// usage:
parseHTML("<p class='wixen'><span>hallo</span></p>");