js的cookie扩展

/*!
* jQuery Cookie Plugin v1.3
* https://github.com/carhartl/jquery-cookie *
* Copyright 2011, Klaus Hartl
* Dual licensed under the MIT or GPL Version 2 licenses.
* http://www.opensource.org/licenses/mit-license.php * http://www.opensource.org/licenses/GPL-2.0 */
(function ($, document, undefined) {

var pluses = /\+/g;

function raw(s) {
return s;
}

function decoded(s) {
return decodeURIComponent(s.replace(pluses, ' '));
}

var config = $.cookie = function (key, value, options) {

// write
if (value !== undefined) {
options = $.extend({}, config.defaults, options);

if (value === null) {
options.expires = -1;
}

if (typeof options.expires === 'number') {
var days = options.expires, t = options.expires = new Date();
t.setDate(t.getDate() + days);
}

value = config.json ? JSON.stringify(value) : String(value);

return (document.cookie = [
encodeURIComponent(key), '=', config.raw ? value : encodeURIComponent(value),
options.expires ? '; expires=' + options.expires.toUTCString() : '', // use expires attribute, max-age is not supported by IE
options.path    ? '; path=' + options.path : '',
options.domain  ? '; domain=' + options.domain : '',
options.secure  ? '; secure' : ''
].join(''));
}

// read
var decode = config.raw ? raw : decoded;
var cookies = document.cookie.split('; ');
for (var i = 0, l = cookies.length; i < l; i++) {
var parts = cookies[i].split('=');
if (decode(parts.shift()) === key) {
var cookie = decode(parts.join('='));
return config.json ? JSON.parse(cookie) : cookie;
}
}

return null;
};

config.defaults = {};

$.removeCookie = function (key, options) {
if ($.cookie(key) !== null) {
$.cookie(key, null, options);
return true;
}
return false;
};

})(jQuery, document);

如何设置cookie的值：
$.cookie('online_user_date',$("#online_user_date").val());
如何获取cookie的值:
$('#online_user_date').val($.cookie('online_user_date'));