title: NodeList changes do not affect length
body: <p>i have created a NodeList with <code>nodeList = document.createDocumentFragment().childNodes;</code>,</p>
  
  <p>then i have set <code>nodeList[0] = document.getElementById("foo");</code></p>
  
  <p>everything works fine, the only problem is, that <code>nodeList.length</code> stays 0</p>
  
  <p>i have allready tried to change an Array to a NodeList. Also i have tried to use a fragment, appended children and changed them afterwards and returned the childnodes.</p>
  
  <p>i cannot just append the original children, because they get removed somewere else then.</p>
  
  <p>what am i missing?</p>
  
  <p>yes i know i could just use an Array, but i want to NodeList element</p>