title: change the class of an element without ID
body: <p>Hi,</p>
  
  <p>I want to change the class of an element that has no ID, so I am doing this</p>
  
  <pre><code>var cols = document.getElementsByClassName('input-box');
          for(i=0; i&lt;cols.length; i++) {
           cols[i].toggleClass('invisible');
          }
  </code></pre>
  
  <p>but it wont work. I get an error that says </p>
  
  <pre><code>cols[i].toggleClass is not a function
  </code></pre>
  
  <p>Why is that?</p>
  
  <p>Thank you.</p>