title: Using capture groups within an NSRegularExpression pattern
body: <p>Is a regex of the following form legit in Obj C? </p>
  
  <pre><code>"&lt;(img|a|div).*?&gt;.*?&lt;/$1&gt;"
  </code></pre>
  
  <p>I know it's valid in JS with a \1 instead of $1, but I'm having little luck in Obj C. </p>