title: Get which day of the week the month starts on for given input
body: <p>I have a function which defines what day of the week the month starts on for the current month:</p>
  
  <pre><code>public function firstDayOfMonth()
      {
          $day =  (int) date("w", strtotime(date('m').'/01/'.date('Y').' 00:00:00'));
          return $day;
      }
  </code></pre>
  
  <p>How would I alter the above, in a way that allows me to get the day of the week the month starts on if I give it input, for example 'June'.</p>