title: Unexpected behaviour with for in a nodelist
body: <p>I have a nodelist with 30 <code>div</code>s and I need to include 1 <code>div</code> every 4 <code>div</code>s but the <code>var 'c'</code> does not change and stack all the <code>div</code>s in the <code>position[6]</code>.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>for (i = 0; i &lt; 8; i++) {
    var pub = "pub-retangulo-";
    var c = 2;
    c += 4;
  
    var o = document.createElement("div");
    o.setAttribute("id", pub.concat(i.toString()));
    o.setAttribute("align", "center");
  
    var container = document.querySelectorAll(".short-summary")[c];
  
    container.parentNode.insertBefore(o, container);
  }</code></pre>
  </div>
  </div>
  </p>