title: Find if a given date is the first monday of the month
body: <p>trying to pass in some validation to check if a given date is the first monday of the month, if it is then do something if not do something else. So far I have come up with this to check the day of week given a date but dont know how to check if it is the first monday of the month, preferably I would like to make this a function.</p>
  
  <pre><code>$first_day_of_week = date('l', strtotime('9/2/2013'));
  // returns Monday
  </code></pre>