title: Trouble with Javascript object properties - Eloquent Javascript example
body: <pre><code>var thing = {"gabba gabba": "hey", "5": 10};
  show(thing["5"]);
  thing["5"] = 20;
  show(thing[2 + 3]); // = 20
  show(thing[2]); // = undefined
  show(thing[3]); // = undefined
  </code></pre>
  
  <p>I do not understand why show(thing[2+3]) = 20 and the other two below it return undefined. What do the 2 and 3 refer to? Could someone help me out with this? Thanks.</p>