title: Identifying Form destination (Spreadsheet AND SHEET)
body: <p>I'm working on a script that interacts with Google Form' response sheet.</p>
  
  <pre><code>FormApp.getActiveForm().getDestinationId()
  </code></pre>
  
  <p>give me the spreadsheet id, but I don't find a way to get the sheet itself.  User can change its name and position, so I need to get its id, like in</p>
  
  <pre><code>Sheet.getSheetId()
  </code></pre>
  
  <p>I also have to determine the number of columns the responses uses.  It's not equal to the number of questions in the form.  I can count the number of items in the form:</p>
  
  <pre><code>Form.getItems().length
  </code></pre>
  
  <p>and then search for gridItems, add the number of rows in each and add them minus one:</p>
  
  <pre><code>+ gridItem.getRows().length - 1
  </code></pre>
  
  <p>Finally, I think there's no way to relate each question with each column in the sheet, but by comparing somehow columns names with items title.</p>
  
  <p>Thank you</p>