title: about formatDate in google appScript
body: <p>here is my script</p>
  
  <pre><code>var timeZone = Session.getScriptTimeZone();
  var date_1  =  parseInt(Utilities.formatDate(new Date(date_1_post), timeZone , "Y"));
  </code></pre>
  
  <p>The value of date_1_post is submitted from form, but when I enter the last 2 dates of year (31/12/2018 &amp; 30/12/2018 ), date_1 will return 2019 not 2018.
  this problem only appear by form submit,when i try to get date_1 in spreadsheet in value (31/12/2018 &amp; 30/12/2018 ),that will return 2018.
  I can't figure out what's wrong of the script.</p>