title: What does (function (x,y){...})(a,b); mean in JavaScript?
body: <p>I saw this function:</p>
  
  <pre><code>(function (x, y, data, lbl, dot) {
      // Function body...
  })(x, y, data[i], labels[i], dot);
  </code></pre>
  
  <p>What is this? A function? Why place a function definition in <code>()</code>?</p>