title: How to add 30 minutes to time as hours and minutes
body: <p>I Have a <code>time</code> variable which is f.ex <code>5:21</code> . I want to add 30 minutes to it, then whatever result is, I want to add 30 minutes to it. How can I do this in javascript?<br>Ie. I want the interval of 30 min to the time I have.</p>
  
  <pre><code>var time = valgraph.datetime; // it's a dynamic time
  var times = time.replace('Z', '');
  var res = times.substr(11, 5); // time AS 5:20
  </code></pre>