title: Is this a valid date in JavaScript?
body: <p>my function returns the selected date of a calendar in this format:</p>
  
  <pre><code>var returnValue = "6.7.2017"; //day.month.year
  </code></pre>
  
  <p>When i try to use it for a new Date, it does not work:</p>
  
  <pre><code>var weekdays = ['Sonntag', 'Montag', 'Dienstag', 'Mittwoch', 'Donnerstag', 'Freitag', 'Samstag'];
  var wkdayname = new Date(returnValue); //Error: returnValue ist NaN
  var dayName = weekdays[wkdayname.getDay()];
  </code></pre>
  
  <p>All I want is just the name of the weekday of this date.</p>
  
  <p>Do you have any suggestions ?</p>