(function($){
$.fn.autotab = function(options) {
	var defaults = {
		format: 'all',			// text, numeric, alphanumeric, all
		maxlength: 2147483647,	// Defaults to maxlength value
		uppercase: false,		// Converts a string to UPPERCASE
		lowercase: false,		// Converts a string to lowecase
		nospace: false,		// Remove spaces in the user input
		target: null,			// Where to auto tab to
		previous: null			// Backwards auto tab when all data is backspaced
	};

	$.extend(defaults, options);

	var check_element = function(name) {
		var val = null;
		var check_id = $('#' + name)[0];
		var check_name = $('input[name=' + name + ']')[0];

		if(check_id != undefined)
			val = $(check_id);
		else if(check_name != undefined)
			val = $(check_name);

		return val;
	};

	var key = function(e) {
		if(!e)
			e = window.event;

		return e.keyCode;
	};

	if(typeof defaults.target == 'string')
		defaults.target = check_element(defaults.target);

	if(typeof defaults.previous == 'string')
		defaults.previous = check_element(defaults.previous);

	var maxlength = $(this).attr('maxlength');

	if(defaults.maxlength == 2147483647 && maxlength != 2147483647)
		defaults.maxlength = maxlength;
	else if(defaults.maxlength > 0)
		$(this).attr('maxlength', defaults.maxlength)
	else
		defaults.target = null;

	if($.browser.msie)
	{
		this.keydown(function(e) {
			if(key(e) == 8)
			{
				var val = this.value;

				if(val.length == 0 && defaults.previous)
					defaults.previous.focus();
			}
		});
	}

	return this.keypress(function(e) {
		if(key(e) == 8)
		{
			var val = this.value;

			if(val.length == 0 && defaults.previous)
				defaults.previous.focus();
		}
	}).keyup(function(e) {
		var val = this.value;

		switch(defaults.format)
		{
			case 'text':
				var pattern = new RegExp('[0-9]+', 'g');
				var val = val.replace(pattern, '');
				break;

			case 'alpha':
				var pattern = new RegExp('[^a-zA-Z]+', 'g');
				var val = val.replace(pattern, '');
				break;

			case 'number':
			case 'numeric':
				var pattern = new RegExp('[^0-9]+', 'g');
				var val = val.replace(pattern, '');
				break;

			case 'alphanumeric':
				var pattern = new RegExp('[^0-9a-zA-Z]+', 'g');
				var val = val.replace(pattern, '');
				break;

			case 'all':
			default:
				break;
		}

		if(defaults.nospace)
		{
			pattern = new RegExp('[ ]+', 'g');
			val = val.replace(pattern, '');
		}

		if(defaults.uppercase)
			val = val.toUpperCase();

		if(defaults.lowercase)
			val = val.toLowerCase();

		this.value = val;

		var keys = [8, 9, 16, 17, 18, 19, 20, 27, 33, 34, 35, 36, 37, 38, 39, 40, 45, 46, 144, 145];
		var string = keys.toString();

		if(string.indexOf(key(e)) == -1 && val.length == defaults.maxlength && defaults.target)
			defaults.target.focus();
	});
};

})(jQuery);