title: Javascript 0 in beginning of number
body: <p>I just want to understand js logic with 0-s in beginning of number.
  For example</p>
  
  <pre><code>var x = 09.3
  // here x == 9.3
  // other example
  09.3 == 9.3
  // returns true
  
  // but check this one
  var x = 02.5
  // Uncaught SyntaxError: Unexpected number
  // or this one
  02.5 == 2.5 
  // same error here
  </code></pre>
  
  <p>Can anyone explain, how it works, why in first example it works, and ignores leading zeros, but in second example it gives me a SyntaxError</p>
  
  <p>Thank you</p>