title: Confusion with javascript array.splice()
body: <p>I'm really confused about this.</p>
  
  <p>My understanding was that <code>array.splice(startIndex, deleteLength, insertThing)</code> would insert <code>insertThing</code> into the result of <code>splice()</code> at <code>startIndex</code> and delete <code>deleteLength</code>'s worth of entries? ... so:</p>
  
  <pre><code>var a = [1,2,3,4,5];
  var b = a.splice(1, 0, 'foo');
  console.log(b);
  </code></pre>
  
  <p>Should give me:</p>
  
  <pre><code>[1,'foo',2,3,4,5]
  </code></pre>
  
  <p>And</p>
  
  <pre><code>console.log([1,2,3,4,5].splice(2, 0, 'foo'));
  </code></pre>
  
  <p>should give me</p>
  
  <pre><code>[1,2,'foo',3,4,5]
  </code></pre>
  
  <p>etc.</p>
  
  <p>But for some reason it's giving me just an empty array? Take a look: <a href="http://jsfiddle.net/trolleymusic/STmbp/3/">http://jsfiddle.net/trolleymusic/STmbp/3/</a></p>
  
  <p>Thanks :)</p>