title: Why does parseInt() return an unexpected result when I pass a string with a leading zero?
body: <p><code>parseInt('1') = 1</code><br>
  <code>parseInt('01') = 1</code><br>
  <code>parseInt('5') = 5</code><br>
  <code>parseInt('05') = 5</code><br>
  <code>parseInt('8') = 8</code>  </p>
  
  <p>But why:<br>
  <code>parseInt('08') = 0</code><br>
  <code>parseInt('09') = 0</code></p>