title: Functions stored in variables? Javascript
body: <p>Could somebody please explain what this notation is in javascript? What is function(d) doing? In this program it seemse that x is called by the following, but I have no idea what any of this means. Thanks in advance...</p>
  
  <pre><code>x = function(d) { return d.x * width / mx; };
  
  // later....
   x({x: .9}); // call
  </code></pre>