gistfile1.js

convert_format = function(time) {
  var hour = Number(time.replace(/:[0-9]+/, '').replace(/ *[a-z]+/, ''))
    , min = Number(time.replace(/[0-9]+:/, '').replace(/ *[a-z]+/, ''))
    , ampm = time.replace(/[0-9]+:/, '').replace(/[0-9]+ */, '');

  if(ampm !== '') {
    // Convert to 24 hour time(Removing ampm)
    // Time: 0:00 - 23:59

    if(hour === 12 && ampm === 'am') hour = 0;
    if(ampm === 'pm' && hour < 12) {
      hour += 12;
    }
    if(hour > 23) hour = 0;

    time = hour + ':' + min;
  } else {
    // Convert to 12 hour time(No ampm previously)
    // Time: 12:00-11:59AM - 12:00-11:59PM

    if(hour < 11) ampm = 'am';
    if(hour >= 12) ampm = 'pm';
    if(hour === 0) {
      hour = 12;
      ampm = 'am';
    }
    if(hour > 12) hour -= 12;

    time = hour + ':' + min + ' ' + ampm;
  }

  return time;
};