(function($) {
	$.fn.autotab = function(options) {
		var defaults = {
			format: 'all',
			maxlength: 2147483647,
			uppercase: false,
			lowercase: false,
			nospace: false,
			target: null,
			previous: null
		};
		$.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) {
						this.blur();
						defaults.previous.focus();
					}
				}
			});
		}
		return this.keypress(function(e) {
			if (key(e) == 8) {
				var val = this.value;
				if (val.length == 0 && defaults.previous) {
					this.blur();
					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) {
				this.blur();
				defaults.target.focus();
			}
		});
	};
})(jQuery);