A jQuery Countdown plugin.

Countdown.js

// Countdown.js
// A plugin to generate a countdown to a date.
// version 1.0, January 2013
// by Andrew Anderson

;(function ( $, window, document, undefined ) {

  var pluginName = "countdown",
		defaults = {
			year: "",
			month: "",
			day: "",
			labels: true,
			includeMS: true
		};

	function Countdown( element, options ) {
		this.element = element;

		this.options = $.extend( {}, defaults, options );

		this._defaults = defaults;
		this._name = pluginName;

		this.init();
	}

	Countdown.prototype = {

		init: function() {
			// Create the DOM elements.
			$container = $(document.createElement('div')).addClass('rd_countdown_container').append(
				$('<span class="days countdown_time"></span> <span class="day_label countdown_label">Days</span> '+
					'<span class="hours countdown_time"></span> <span class="hour_label countdown_label">Hours</span> '+
					'<span class="minutes countdown_time"></span> <span class="minute_label countdown_label">Minutes</span> ' +
					'<span class="seconds countdown_time"></span> <span class="second_label countdown_label">Seconds</span> '+
					'<span class="ms countdown_time"></span> <span class="ms_label countdown_label">ms</span>'
				)
			);
			// Initiate the settings.
			if(this.options.labels === false) { $container.children('.countdown_label').hide(); }
			if(this.options.includeMS === false) { $container.children('.ms, .ms_label').hide(); }

			// Insert into the element, replacing all child nodes:
			$(this.element).html($container);

			// Convert the date. Note the subtraction of 1 from the month to convert to index of 0.
			this.options.endDate = new Date(this.options.year, this.options.month - 1, this.options.day);

			// Start the timer.
			this.intervalTimer = setInterval($.proxy(this._updateCountdown, this), 75);
		},

		_updateCountdown: function(e) {
			var x = 0;
			var ms = this.options.endDate - new Date();
			x = ms / 1000;
            var sec = Math.floor(x % 60);
			x = x / 60;
			var min = Math.floor(x % 60);
			x = x / 60;
			var hr = Math.floor(x % 24);
			var day = Math.floor(x / 24);

			$('.rd_countdown_container .days').text(day);
			$('.rd_countdown_container .hours').text(hr);
			$('.rd_countdown_container .minutes').text(min);
			$('.rd_countdown_container .seconds').text(sec);
			$('.rd_countdown_container .ms').text(this._pad(ms % 1000, 3));
		},
      
        _pad: function(num, size) {
          var s = "000000000" + num;
          return s.substr(s.length-size);
        },

		stop: function() {
			clearInterval(this.intervalTimer);
		}
	};

	$.fn[pluginName] = function ( options ) {
        var args = arguments;
        if (options === undefined || typeof options === 'object') {
            return this.each(function () {
                if (!$.data(this, 'plugin_' + pluginName)) {
                    $.data(this, 'plugin_' + pluginName, new Countdown( this, options ));
                }
            });
        } else if (typeof options === 'string' && options[0] !== '_' && options !== 'init') {
            return this.each(function () {
                var instance = $.data(this, 'plugin_' + pluginName);
                if (instance instanceof Countdown && typeof instance[options] === 'function') {
                    instance[options].apply( instance, Array.prototype.slice.call( args, 1 ) );
                }
            });
        }
    };

})( jQuery, window, document );

Use like this. Months should be passed normal date months, such as June = 6.

$(".countdownContainer").countdown({year: 2013, month: 6, day: 17});