title: Combining regular expressions in Javascript
body: <p>Is it possible to combine regular expressions in javascript.</p>
  
  <p>For ex: </p>
  
  <pre><code> var lower = /[a-z]/;
   var upper = /[A-Z]/;
   var alpha = upper|lower;//Is this possible?
  </code></pre>
  
  <p>ie. can i assign regular expressions to variables and combine those variables using pattern matching characters as
   we do in regular expressions</p>