title: "Unexpected quantifier" error with javascript regex
body: <p>When I use this regex declaration in javascript:</p>
  
  <pre><code>var phoneRegExp = /^(\+\s?)?((?&lt;!\+.*)\(\+?\d+([\s\-\.]?\d+)?\)|\d+)([\s\-\.]?(\(\d+([\s\-\.]?\d+)?\)|\d+))*(\s?(x|ext\.?)\s?\d+)?$/i;
  </code></pre>
  
  <p>it gives me an "Unexpected quantifier" error in IE10.
  Chrome reports an "Invalid group".
  As far as I can see the expression is ok, I have tested it with <a href="http://regexhero.net/tester" rel="nofollow">http://regexhero.net/tester</a> and it is the same as is used in the .NET4.5 PhoneAttribute</p>
  
  <p>Any ideas?</p>