title: JavaScript check if timezone name valid or not
body: <p>Is there a way to check if timezone name valid or not in JavaScript without using external library?</p>
  
  <p>When user enters timezone name in text field I want to verify whether zone is valid or not?</p>
  
  <p>I know we can do it easily using moment-timezone library. But I don't want to use any extra library. I'm looking for pure JavaScript way.</p>
  
  <pre><code>isValidTimeZone(name) {
  //return true/false  
  }
  
  isValidTimeZone('Asia/Colombo'); //returns true
  isValidTimeZone('America/Los_Angeles'); //returns true
  isValidTimeZone('MyTimeZone/ME'); //returns false
  </code></pre>