title: Extract dates from HTML week picker
body: <p>Is it possible to get the days/dates of the selected week of a html week picker (in vanilla JS). For example </p>
  
  <pre><code>&lt;input type="week" name="week" id="copyWeekInput"&gt;
  </code></pre>
  
  <p>and then </p>
  
  <pre><code>document.querySelector("#copyWeekInput")... // for week 18, return something like ["2020-04-27", "2020-04-28", "2020-04-29", "2020-04-30", "2020-05-01", "2020-05-02", "2020-05-03"]
  </code></pre>
  
  <p>It's strange that they're there in the UI, but I can't find them in the input week's object. </p>
  
  <p>Thanks. </p>