Question about javascript function declaration
<p>What does it mean when a javascript function is declared in the following way:</p>

<pre><code>JSON.stringify = JSON.stringify || function (obj)
{
  //stuff
};
</code></pre>

<p>How is the above different from just declaring it like below?</p>

<pre><code>function stringify(obj)
{
  //stuff
}
</code></pre>
