title: Validate Date before submitting Google form
body: <p>I have a Google sheet -"A". A google form- "B" and google form response sheet- "C". 
  There is a date mentioned in "A". Form "B" asks for many responses, out of which date is one of them.</p>
  
  <p>Logic:- Before submitting the form "B", I want to make sure that the date entered by user is greater than the date already mentioned in "A". </p>
  
  <p>If logic is true submit form. Else display- form can not be submitted.  </p>
  
  <p>I can extract date from sheet "A". But I am not able to push or read or validate date entry done in form "B". </p>
  
  <p>I am writing the script in Google forms.</p>
  
  <pre><code>function datevalidate() {
    var Sheet= SpreadsheetApp.openById("avbchfhlhasf").getSheetByName("Booking");
    var Origdate= Sheet.getRange(2, 9).getValues()[0];
  
    var form = FormApp.openById("jhkjdshfkjasdfk");
    var item= form.getItems(FormApp.ItemType.DATE);
  
    Logger.log(item[0]);
  
  
    }
  </code></pre>
  
  <p>i expect the date of "B"- in code "item " to be validated with date of "A" in code "Origdate"- BEFORE submitting the form.</p>