title: Why "TypeError: f is not a function"?
body: <p>Here is example:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var f = function(x) {
     alert(x)
  }
  
  (function() {
     f(1)
  }())</code></pre>
  </div>
  </div>
  </p>
  
  <p>Why</p>
  
  <blockquote>
    <p>TypeError: f is not a function"?</p>
  </blockquote>