title: What is this practice called in JavaScript?
body: <p>When you wrap your JavaScript code in a function like this:</p>
  
  <pre><code>(function(){
  
    var field = ...;
    function doSomthing(){...
    ...
  
  
  })();
  </code></pre>
  
  <p>I noticed that this fixes scoping problems for me on a lot of web pages. What is this practice called?</p>