title: How to use querySelectorAll only for elements that have a specific attribute set?
body: <p>I'm trying to use <code>document.querySelectorAll</code> for all checkboxes that have the <code>value</code> attribute set.</p>
  
  <p>There are other checkboxes on the page that do not have <code>value</code> set, and the value is different for each checkbox. The ids and names are not unique though.</p>
  
  <p>Example:
      <code>&lt;input type="checkbox" id="c2" name="c2" value="DE039230952"/&gt;</code></p>
  
  <p>How do I select just those checkboxes that have values set?</p>