Javascript Clock based on timeZone to overcome moment issue https://github.com/moment/moment-timezone/issues/66

clock.js

Clock = function (timeZone) {
    this.timeZone = timeZone;
};

Clock.prototype = {

    now: function () {
        var nowZone = moment.tz(this.timeZone).zone();
        return moment().zone(nowZone);
    },

    /**
     * parse a ISO8601 string with tz information
     */
    parse: function (o) {
        if (/^(\d{4}\-\d\d\-\d\d([tT][\d:\.]*)?)([zZ]|([+\-])(\d\d):(\d\d))$/.test(o)) {
            var from = moment.parseZone(o),
                fromZ = from.zone(),
                to = from.tz(this.timeZone),
                toZ = to.zone();
            return to.add(fromZ - toZ, 'minutes');
        }
        throw new Error('Missing timeZone information');
    },

    /**
     * parse as a day from [y,m,d] or String or Date
     */
    parseDay: function (o) {
        var mom = this.today(), y, m, d, z;
        if (typeof o === 'string') {
            mom = moment.parseZone(o);
            y = mom.year();
            m = mom.month();
            d = mom.date();
        } else if (o instanceof Array) {
            y = o.length > 0 ? o[0] : mom.year();
            m = o.length > 1 ? o[1] : mom.month();
            d = o.length > 2 ? o[2] : mom.date();
        } else if (o instanceof Date) {
            y = o.getFullYear();
            m = o.getMonth();
            d = o.getDate();
        } else {
            y = mom.year();
            m = mom.month();
            d = mom.date();
        }
        mom = moment.parseZone([y, m, d]);
        z = mom.zone();
        return mom.tz(this.timeZone).subtract(z, 'minutes');
    },

    today: function () {
        return this.now().clone().startOf('day');
    },

    toString: function () {
        return this.now().format();
    }

};

var clock = new Clock('Europe/Paris');

[clock.parse('2014-03-25T08:00:00-04:00').format(), clock.parse('2014-03-01T08:00:00-05:00').format(), clock.parse('2014-04-15T08:00:00-04:00').format()]

outputs

["2014-03-25T13:00:00+01:00", "2014-03-01T14:00:00+01:00", "2014-04-15T14:00:00+02:00"]

and

var clock = new Clock('Europe/Paris');
[clock.parseDay([2014, 2, 1]).format(), clock.parseDay([2014, 3, 1]).format()]

outputs

["2014-03-01T00:00:00+01:00", "2014-04-01T00:00:00+02:00"]