title: Invalid date in IE11 even though date format is ISO 8601 supported
body: <p>I have used moment to convert date to ISO supported format as it's working fine on chrome &amp; firefox but not on IE11 so 
  I as per the docs YYYY-MM-DD is supported iso format,
  here my js_time1 format is as mentioned ddd MMM D YYYY hh:mm:ss
  so i have used this to fomrat it</p>
  
  <pre><code>var js_time = moment(js_time1).format('YYYY-MM-DD');
  </code></pre>
  
  <p>i have also tried 
   <code>var js_time = moment(js_time1,'ddd MMM D YYYY hh:mm:ss').format('YYYY-MM-DD');</code>
   but no use.
  Format for js_time1 is Mon Aug 3rd 2018 12:12:21
  Thanks in advance</p>