(function($){
	$.fn.ipaddress = function() {
		return $(this).each(function(){
			var $this = $(this);

			if (!$this.hasClass('ip-enabled')) {
				$this.hide();

				var ip_value = (this.value) ? this.value.split('.') : ['','','',''];

				var octets = [];
				var id_prefix = $this.attr('name').replace(/\[/g, '_').replace(/\]/g, '');
				for (var i = 0; i <=3; i++) {
					octets.push('<input type="text" class="ip_octet" id="' + id_prefix + '_octet_' + (i+1) + '" maxlength="3" value="' + ip_value[i] + '" />');
				}
				var octet_html = octets.join('.');
				$this.after($('<div class="ip_container" style="display: inline' + (($.browser.msie) ? '' : '-block') + ';"/>').html(octet_html));
				$this.addClass('ip-enabled');
			}

			var isNumeric = function(e){
				if (e.shiftKey) return false;
				return (e.keyCode >= 48 && e.keyCode <= 57) || (e.keyCode >= 96 && e.keyCode <= 105);
			};

			var isValidKey = function(e){
				var valid = [
					8,        // backspace
					9,        // tab
					13,       // enter
					27,       // escape
					35,       // end
					36,       // home
					37,       // left arrow
					39,       // right arrow
					46,       // delete
					48, 96,   // 0
					49, 97,   // 1
					50, 98,   // 2
					51, 99,   // 3
					52, 100,  // 4
					53, 101,  // 5
					54, 102,  // 6
					55, 103,  // 7
					56, 104,  // 8
					57, 105,  // 9
					110, 190  // period
				];

				// only allow shift key with tab
				if (e.shiftKey && e.keyCode != 9) return false;

				for (var i = 0, c; c = valid[i]; i++) {
					if (e.keyCode == c) return true;
				}

				return false;
			};

			$('input.ip_octet').bind('keydown', function(e){
				if (!isValidKey(e)) return false;

				var next_octet = $(this).next('input.ip_octet');
				var prev_octet = $(this).prev('input.ip_octet');

				// jump to next octet on period if this octet has a value
				if (e.keyCode == 110 || e.keyCode == 190) {
					if ($(this).val().length) {
						if (next_octet.length) {
							next_octet.focus();
							next_octet.select();
						}
					}
					return false;
				}

				if (($(this).caret()[1] - $(this).caret()[0]) && isNumeric(e)) {
					return true;
				}

				// jump to next octet if maxlength is reached and number key or right arrow is pressed
				if ((this.value.length == this.getAttribute('maxlength') && $(this).caret()[0] == this.getAttribute('maxlength') && (isNumeric(e) || e.keyCode == 39)) || (e.keyCode == 39 && $(this).caret()[0] == this.value.length)) {
					if (next_octet.length) {
						$(this).trigger('blur');
						next_octet.focus().caret(0);
						return true;
					}
				}

				// jump to previous octet if left arrow is pressed and caret is at the 0 position
				if (e.keyCode == 37 && $(this).caret()[0] == 0) {
					if (prev_octet.length) {
						$(this).trigger('blur');
						prev_octet.caret(prev_octet.val().length);
						return false;
					}
				}

				// jump to previous octet on backspace
				if (e.keyCode == 8 && $(this).caret()[0] == 0 && $(this).caret()[0] == $(this).caret()[1]) {
					if (prev_octet.length) {
						$(this).trigger('blur');
						prev_octet.focus().caret(prev_octet.val().length);
						return false;
					}
				}
 		}).bind('keyup', function(e){
				// save value to original input if all octets have been entered
				if ($('input.ip_octet', $(this).parent()).filter(function(){ return this.value.length; }).length == 4) {
					var ip_value = [];
					$('input.ip_octet', $(this).parent()).each(function(){
						ip_value.push(this.value);
					});
					$this.val(ip_value.join('.'));
				}
			}).bind('blur', function(){
				if (this.value > 255) this.value = 255;
			});

		});

	};
})(jQuery);