Run a podcast? Here's a little JavaScript function to test if your show is currently "On the Air".

onAir.js

/**
 * onAir.js
 * 
 * @param   {string} day [the day your show airs (eg. "Tuesday")]
 * @param   {string} start [start time of the show in 24hr format (eg. "13:00")]
 * @param   {string} end [stop time of the show in 24hr format (eg. "14:30")]
 * @param   {string} timezone [the UTC time zone of your show (eg. "-6" for Central Time)]
 * @return  {bool}
 */ 
var onAir = function (day, start, end, timezone) {
  var local, utc, show, days, onAir, startValues, endValues, startTime, endTime,
      startMinutes, endMinutes, showMinutes;
  
  // by default, we are not on air    
  onAir = false;
  
  // map day numbers to indexes
  days = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Firday', 'Saturday'];
  
  // convert start/end times to date objects
  startValues = start.split(':');
  endValues = end.split(':');
  startTime = new Date();
  endTime = new Date();
  startTime.setHours(startValues[0], startValues[1]);
  endTime.setHours(endValues[0], endValues[1]);
  
  // add the hours minutes together to get total minutes
  startMinutes = (startTime.getHours() * 60) + startTime.getMinutes();
  endMinutes = (endTime.getHours() * 60) + endTime.getMinutes();
  
  // get the current local time
  local = new Date();
  
  // get the current time in the show's timezone
  utc = local.getTime() + (local.getTimezoneOffset() * 60000);
  show = new Date(utc + (3600000*timezone));
  
  // convert the show hours + minutes to just minutes
  showMinutes = (show.getHours() * 60) + show.getMinutes();
  
  // test to see if the show is going on right now
  if (days[show.getDay()] === day && (showMinutes >= startMinutes && showMinutes <= endMinutes)) {
    onAir = true;
  }
  
  return onAir;
}

usage.md

onAir.js

Hey podcasters! I wrote this little function for a SO question and thought it might be useful to someone else.

It's a quick true/false test to see if your show is on the air!

Example

Let's say I host a show from 2:00-2:30pm Central Time (-6 UTC). Here's how to test that using onAir.js

var isShowing = onAir('Tuesday', '14:00', '14:30', '-6');

Now isShowing will be either true or false if our show is currently airing!

Add some jQuery

A practice use case for this function would be show or hide a <div> on your page if your show is on the air:

$(document).ready(function () {
  // test if our show is live
  var isShowing = onAir('Tuesday', '14:00', '14:30', '-6');

  // show our div if we are!
  if (isShowing) {
    $('#wearelive').show();
  }
});