title: Comma Operator PHP
body: <p>Both these statements are true:</p>
  
  <pre><code>$_POST['foo'] = $_POST['bar'] = 'some string';
  
  //1. with '&amp;&amp;' operator
  if(isset($_POST['foo']) &amp;&amp; isset($_POST['bar'])) { 
      echo true; 
  }
  
  //2. with a comma
  if(isset($_POST['foo'], $_POST['bar'])) { 
      echo true; 
  }
  </code></pre>
  
  <p>What is the difference (if any) between them?</p>