title: RegEx standards across languages
body: <p>I am asking this question because I notice there are some slight differences in the syntax of RegEx between different languages. </p>
  
  <p>I am wondering if there is a RegEx standard that is maintained somewhere? And if so, where can I find this document? Also, if I create a RegEx expression in .NET, is the same expression guaranteed to be 100% compatible and work with other languages, such as Perl or Javascript or Java? </p>
  
  <p>Finally, are there any "best practices" when it comes to using RegEx that can help to make it more maintainable across other platform languages?</p>