title: javascript regex validate years in range
body: <p>I have input field for year and I need a regex for validation it.
  I have such code: <code>^([12]\d)?(\d\d)$</code>.
  But I want allow to validate only years in certain range (1990-2010, for example). How can I do it?</p>
  
  <p>Edit. range must be 1950-2050</p>