jquery中的cookie操作

/*!
 * jQuery Cookie Plugin v1.4.1
 * https://github.com/carhartl/jquery-cookie
 *
 * Copyright 2006, 2014 Klaus Hartl
 * Released under the MIT license
 */
(function (factory) {
    if (typeof define === ‘function‘ && define.amd) {
        // AMD (Register as an anonymous module)
        define([‘jquery‘], factory);
    } else if (typeof exports === ‘object‘) {
        // Node/CommonJS
        module.exports = factory(require(‘jquery‘));
    } else {
        // Browser globals
        factory(jQuery);
    }
}(function ($) {

    var pluses = /\+/g;

    function encode(s) {
        return config.raw ? s : encodeURIComponent(s);
    }

    function decode(s) {
        return config.raw ? s : decodeURIComponent(s);
    }

    function stringifyCookieValue(value) {
        return encode(config.json ? JSON.stringify(value) : String(value));
    }

    function parseCookieValue(s) {
        if (s.indexOf(‘"‘) === 0) {
            // This is a quoted cookie as according to RFC2068, unescape...
            s = s.slice(1, -1).replace(/\\"/g, ‘"‘).replace(/\\\\/g, ‘\\‘);
        }

        try {
            // Replace server-side written pluses with spaces.
            // If we can‘t decode the cookie, ignore it, it‘s unusable.
            // If we can‘t parse the cookie, ignore it, it‘s unusable.
            s = decodeURIComponent(s.replace(pluses, ‘ ‘));
            return config.json ? JSON.parse(s) : s;
        } catch(e) {}
    }

    function read(s, converter) {
        var value = config.raw ? s : parseCookieValue(s);
        return $.isFunction(converter) ? converter(value) : value;
    }

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

        // Write

        if (arguments.length > 1 && !$.isFunction(value)) {
            options = $.extend({}, config.defaults, options);

            if (typeof options.expires === ‘number‘) {
                var days = options.expires, t = options.expires = new Date();
                t.setMilliseconds(t.getMilliseconds() + days * 864e+5);
            }

            return (document.cookie = [
                encode(key), ‘=‘, stringifyCookieValue(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 result = key ? undefined : {},
            // To prevent the for loop in the first place assign an empty array
            // in case there are no cookies at all. Also prevents odd result when
            // calling $.cookie().
            cookies = document.cookie ? document.cookie.split(‘; ‘) : [],
            i = 0,
            l = cookies.length;

        for (; i < l; i++) {
            var parts = cookies[i].split(‘=‘),
                name = decode(parts.shift()),
                cookie = parts.join(‘=‘);

            if (key === name) {
                // If second argument (value) is a function it‘s a converter...
                result = read(cookie, value);
                break;
            }

            // Prevent storing a cookie that we couldn‘t decode.
            if (!key && (cookie = read(cookie)) !== undefined) {
                result[name] = cookie;
            }
        }

        return result;
    };

    config.defaults = {};

    $.removeCookie = function (key, options) {
        // Must not alter options, thus extending a fresh object...
        $.cookie(key, ‘‘, $.extend({}, options, { expires: -1 }));
        return !$.cookie(key);
    };

}));

1.$.cookie(cookieName, cookieValue);　　//cookieName:要设置的cookie名称，cookieValue表示相对应的值。
注：当没有指明 cookie有效时间时，所创建的cookie有效期默认到用户关闭浏览器为止，所以被称为“会话cookie（session cookie）”。 

2.$.cookie(cookieName, cookieValue, { expires: 7 }); //创建一个cookie并设置有效时间为 7天: 
注：当指明了cookie有效时间时，所创建的cookie被称为“持久 cookie （persistent cookie）”。

3.$.cookie(‘the_cookie‘, ‘the_value‘, { expires: 7, path: ‘/‘ }); //创建一个cookie并设置 cookie的有效路径：

注：在默认情况下，只有设置 cookie的网页才能读取该 cookie。如果想让一个页面读取另一个页面设置的cookie，必须设置cookie的路径。cookie的路径用于设置能够读取 cookie的顶级目录。将这 

个路径设置为网站的根目录，可以让所有网页都能互相读取 cookie （一般不要这样设置，防止出现冲突）

$.cookie(‘the_cookie‘); // cookie存在 => ‘the_value‘ 

$.cookie(‘not_existing‘); // cookie不存在 => null 

$.cookie(‘the_cookie‘, null); 
$.cookie(‘the_cookie‘, ‘‘); 
$.cookie(‘the_cookie‘, ‘‘, { expires: -1 });