jQuery.fn.countdown = function(userOptions)
{
  // Default options
  var options = {
	stepTime: 60,
	// startTime and format MUST follow the same format.
	// also you cannot specify a format unordered (e.g. hh:ss:mm is wrong)
	format: "dd:hh:mm:ss",
	startTime: "01:12:32:55",
	digitImages: 6,
	digitWidth: 20,
	digitHeight: 30,
	timerEnd: function(){},
	image: "digits.png"
  };
  var digits = [], interval;

  // Draw digits in given container
  var createDigits = function(where) 
  {
	var c = 0;
	// Iterate each startTime digit, if it is not a digit
	// we'll asume that it's a separator
	for (var i = 0; i < options.startTime.length; i++)
	{
	  if (parseInt(options.startTime[i]) >= 0) 
	  {
		elem = $('<div id="cnt_' + i + '" class="cntDigit" />').css({
		  height: options.digitHeight * options.digitImages * 10, 
		  float: 'left', background: 'url(\'' + options.image + '\')',
		  width: options.digitWidth});
		digits.push(elem);
		margin(c, -((parseInt(options.startTime[i]) * options.digitHeight *
							  options.digitImages)));
		digits[c].__max = 9;
		// Add max digits, for example, first digit of minutes (mm) has 
		// a max of 5. Conditional max is used when the left digit has reach
		// the max. For example second "hours" digit has a conditional max of 4 
		switch (options.format[i]) {
		  case 'h':
			digits[c].__max = (c % 2 == 0) ? 2: 9;
			if (c % 2 == 0)
			  digits[c].__condmax = 4;
			break;
		  case 'd': 
			digits[c].__max = 9;
			break;
		  case 'm':
		  case 's':
			digits[c].__max = (c % 2 == 0) ? 5: 9;
		}
		++c;
	  }
	  else 
		elem = $('<div class="cntSeparator"/>').css({float: 'left'})
				.text(options.startTime[i]);

	  where.append(elem)
	}
  };

  // Set or get element margin
  var margin = function(elem, val) 
  {
	if (val !== undefined)
	  return digits[elem].css({'marginTop': val + 'px'});

	return parseInt(digits[elem].css('marginTop').replace('px', ''));
  };

  // Makes the movement. This is done by "digitImages" steps.
  var moveStep = function(elem) 
  {
	digits[elem]._digitInitial = -(digits[elem].__max * options.digitHeight * options.digitImages);
	return function _move() {
	  mtop = margin(elem) + options.digitHeight;
	  if (mtop == options.digitHeight) {
		margin(elem, digits[elem]._digitInitial);
		if (elem > 0) moveStep(elem - 1)();
		else 
		{
		  clearInterval(interval);
		  for (var i=0; i < digits.length; i++) margin(i, 0);
		  options.timerEnd();
		  return;
		}
		if ((elem > 0) && (digits[elem].__condmax !== undefined) && 
			(digits[elem - 1]._digitInitial == margin(elem - 1)))
		  margin(elem, -(digits[elem].__condmax * options.digitHeight * options.digitImages));
		return;
	  }

	  margin(elem, mtop);
	  if (margin(elem) / options.digitHeight % options.digitImages != 0)
		setTimeout(_move, options.stepTime);

	  if (mtop == 0) digits[elem].__ismax = true;
	}
  };

  $.extend(options, userOptions);
  this.css({height: options.digitHeight, overflow: 'hidden'});
  createDigits(this);
  interval = setInterval(moveStep(digits.length - 1), 1000);
};