title: Javascript - What kind of javascript class that use in this code?
body: <p>I have found a <a href="http://www.photoswipe.com/" rel="nofollow">JavaScript gallery</a>.</p>
  
  <p>When I view the JavaScript code, I really don't understand how to write code in this style. What is the style called? Where can I find documents related to it?</p>
  
  <p>Note: what i want to know is the way that define Class in this code</p>
  
  <p>(function (){ ... })(window)</p>
  
  <p>what is style ?</p>