JavaScript ISO 8601 date

iso_date.js

/**
 * ISO 8601 date
 * @see http://webcloud.se/log/JavaScript-and-ISO-8601/
 * @example "2008-07-09T16:13:30+12:00"
 */

function IsoDate() {};

// Date inheritance

IsoDate.prototype = new Date();

// Public methods

/**
 * Set date parsing ISO 8601 format
 * 
 * @param iso String
 */
IsoDate.prototype.parse = function iso_date_parse(iso) {
  var regexp = "([0-9]{4})(-([0-9]{2})(-([0-9]{2})" +
    "(T([0-9]{2}):([0-9]{2})(:([0-9]{2})(\.([0-9]+))?)?" +
    "(Z|(([-+])([0-9]{2}):([0-9]{2})))?)?)?)?";
  var d = iso.match(new RegExp(regexp));
  
  var offset = 0;
  var date = new Date(d[1], 0, 1);
  
  if (d[3]) { 
    date.setMonth(d[3] - 1); 
  }
  if (d[5]) { 
    date.setDate(d[5]); 
  }
  if (d[7]) { 
    date.setHours(d[7]); 
  }
  if (d[8]) { 
    date.setMinutes(d[8]); 
  }
  if (d[10]) { 
    date.setSeconds(d[10]); 
  }
  if (d[12]) { 
    date.setMilliseconds(Number("0." + d[12]) * 1000); 
  }
  if (d[14]) {
    offset = (Number(d[16]) * 60) + Number(d[17]);
    offset *= ((d[15] == '-') ? 1 : -1);
  }
  
  offset -= date.getTimezoneOffset();
  var time = (Number(date) + (offset * 60 * 1000));
  this.setTime(Number(time));
};

// Static methods

/**
 * Exports to ISO 8601 format
 * 
 * @return String
 */
IsoDate.toIsoString = function iso_date_to_iso_string(date) {
  function pad(n) {
    return n < 10 ? '0' + n : n
  }
  function offset(n) {
    return n < 0 ? '-' + pad(n * -1) : '+' + pad(n);
  }
  
  return date.getUTCFullYear() + '-'
    + pad(date.getUTCMonth()) + '-'
    + pad(date.getUTCDate()) + 'T'
    + pad(date.getUTCHours()) + ':'
    + pad(date.getUTCMinutes()) + ':'
    + pad(date.getUTCSeconds())
    + offset(date.getTimezoneOffset()/60) + ':00';
};