All the parts we use to convert dates on the page to local times

local-conversion.js

var date = new Date();
var offset = date.getTimezoneOffset();
$.cookie('tzoffset', offset, { path: '/' })


/**
 * Add age-based class name
 */
$this.find('p.date .timestamp').each(function() {
  var el = $(this), 
      date = $.parseUTCDate(el.attr('title')),
      age  = '',
      diff = ((new Date()).getTime() - date.getTime()) / 1000 / 60 / 60; // convert to hours
  
  if(diff >= 2 * 7 * 24)  age = 'oldest'; // Two weeks
  else if(diff >= 7 * 24) age = 'old';    // One week 
  else if(diff >= 3 * 24) age = 'stale';  // 3 days
  else if (diff >= 12)    age = 'fresh';
  else                    age = 'new';
  
  el.addClass('age-' + age);  
});


/**
 * Convert any span.timestamp to the users local time and make it relative
 * if required
 */
$('span.timestamp').each(function() {
  var $this = $(this);
  if($this.hasClass('parsed')) return;
  var utc = $.edate.parseUTC($this.text()),
      rel = $this.attr('rel');
      
  if(rel == 'words') {
    output = $.edate.timeAgoInWords(utc)
  } else if(rel == 'words_old') {
    output = $.edate.timeAgoInWords(utc)
    output.replace('ago', 'old')
  } else {
    output = $.edate.strftime(utc, rel)
  }
  
  $this.text(output).addClass('parsed')
})

/**
 * Parse a date as UTC
 */
$.parseUTCDate = function(value) {
  var localDate = new Date(value);
  var utcSeconds = Date.UTC(localDate.getFullYear(), localDate.getMonth(), localDate.getDate(), localDate.getHours(), localDate.getMinutes(), localDate.getSeconds());
  return new Date(utcSeconds);
};