Javascript Date format()

Date.prototype.format = function( )
{
  var yyyy = this.getFullYear().toString();
  var mm = (this.getMonth()+1).toString();
  var dd = this.getDate().toString();

  return yyyy + (mm[1] ? mm : '0'+mm[0]) + (dd[1] ? dd : '0' +dd[0])
}

Date.prototype.format = function () {
  'use strict';/*  w w  w .  j a v  a  2  s.com*/

  var
      d = this.getDate()
    , m = this.getMonth() + 1
    , y = this.getFullYear();

    return '' + y + '-' + (m<=9 ? '0' + m : m) + '-' + (d <= 9 ? '0' + d : d);
};

function ISODateString(aDate) {
  function pad(aNumber) {
    return aNumber < 10 ? '0' + aNumber : aNumber;
  }//from w ww . j  a va2 s  .  c  o  m

  return aDate.getUTCFullYear() + '-' +
         pad(aDate.getUTCMonth() + 1) + '-' +
         pad(aDate.getUTCDate());
}

// For convenience...
Date.prototype.format = function () {
  return ISODateString(this);
};

Date.prototype.format = function () {
    var dt = this;
    return dt.getFullYear().pad(4) + '-' + (dt.getMonth() + 1).pad(2) + '-' + dt.getDay().pad(2)
        + ' ' + dt.getHours().pad(2) + ':' + dt.getMinutes().pad(2);
}

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

function ISODateString(aDate) {
  function pad(aNumber) {
    return aNumber < 10 ? '0' + aNumber : aNumber;
  }/* ww w .  ja va2 s.com*/

  return aDate.getUTCFullYear() + '-' +
         pad(aDate.getUTCMonth() + 1) + '-' +
         pad(aDate.getUTCDate());
}

// For convenience...
Date.prototype.format = function () {
  return ISODateString(this);
};