Untitled

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>
  <ul>
    <li>cosa01</li>
    <li>cosa02</li>
    <li>cosa03</li>
    <li>cosa04</li>
    <li>cosa05</li>
  </ul>
<script id="jsbin-javascript">
var myNode = document.querySelectorAll(('li'));

for (i=0; i<myNode.length; i++) {
  myNode[i].className = 'bob';
});
</script>


<script id="jsbin-source-javascript" type="text/javascript">var myNode = document.querySelectorAll(('li'));

for (i=0; i<myNode.length; i++) {
  myNode[i].className = 'bob';
});</script></body>
</html>