title: Javascript Date.UTC() function is off by a month?
body: <p>I was playing around with Javascript creating a simple countdown clock when I came across this strange behavior:</p>
  
  <pre><code>var a = new Date(), 
  now = a.getTime(),
  then = Date.UTC(2009,10,31),
  diff = then - now,
  daysleft = parseInt(diff/(24*60*60*1000));
  console.log(daysleft );
  </code></pre>
  
  <p>The days left is off by 30 days.</p>
  
  <p>What is wrong with this code?</p>
  
  <p>Edit: I changed the variable names to make it more clear. </p>