title: Retrieve unselected option in a select list using Flask
body: <p>What's up guy?</p>
  
  <p>I'm working on a Flask project using a multiple select form see: <a href="http://jsfiddle.net/nzdak7aL/1/" rel="nofollow noreferrer">http://jsfiddle.net/nzdak7aL/1/</a> for an example of.</p>
  
  <p>I want to submit all items inside the boxes to a flask back-end environment via POST method.
  If I select all items in all boxes before clicking the submit button I can get the data using <code>request.form</code> (and its variation) on flask.</p>
  
  <p><a href="https://i.stack.imgur.com/UrkBS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UrkBS.png" alt="enter image description here"></a></p>
  
  <p>This I get only the items <code>Nick Fury</code> and <code>The Hulk</code> but not <code>Iron Man</code>.</p>
  
  <p>So I can't get the items if I do not select them.</p>
  
  <p><a href="https://i.stack.imgur.com/PjUJX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PjUJX.png" alt="enter image description here"></a></p>
  
  <p>It doesn't return anything, but I need the items in this box.</p>
  
  <p>I already tried set the name as a list <code>name="boxName[]"</code> but it didn't work. Returns always <code>None</code> or <code>[]</code>.</p>