What is the difference between object keys with quotes and without quotes?
<p>Is there any difference between</p>

<pre><code>obj = {'foo':'bar'} 
</code></pre>

<p>and</p>

<pre><code>obj = {foo: 'bar'}
</code></pre>

<p>I have noticed that you can't use <code>-</code> in the key when you don't use the quotes. But does it actually make a difference? If yes, what is it?</p>
