$.cookie('f_city','北京|101010100|,锦州|101070701|',{expires: 999, path: '/',domain: 'weather.com.cn'})

$.cookie('f_city',null,{ path: '/'})   //删除当前域 www.weather.com.cn域下的 f_city

$.cookie('f_city',null,{ path: '/', domain: 'weather.com.cn'})   //删除 .weather.com.cn域下的 f_city

var cookie_f_city= $.cookie('f_city'); //读取cookie只有一种写法，不接受｛domain｝参数，也就是说，当有域同名参数时，只读创建最早的 f_city

/**

 * Cookie plugin

 *

 * Copyright (c) 2006 Klaus Hartl (stilbuero.de)

 * Dual licensed under the MIT and GPL licenses:

 * http://www.opensource.org/licenses/mit-license.php

 * http://www.gnu.org/licenses/gpl.html

 *

 */

/**

 *

 *1、设置cookie的值，比如我们要设置变量名为userid对应值为123的cookie，代码如下：

 * $.cookie('userid','123');

 *

 *2、新建一个cookie，并设置cookie的有效期 路径 域名等，代码如下：

 * $.cookie('userid, '123', {expires: 7, path: '/', domain: 'jquery.com', secure: true});注意：如果去掉后面{}的参数，新建后将以默认设置生效。

 *

 *3、删除cookie，即把对应cookie值置为null，代码如下：

 * $.cookie('userid', null);

 *

 *4、读取cookie，如读取变量名为userid的cookie值，代码如下：

 * var uId= $.cookie('userid');

 *

 */

/**

 * Get the value of a cookie with the given name.

 *

 * @example $.cookie('the_cookie');

 * @desc Get the value of a cookie.

 *

 * @param String name The name of the cookie.

 * @return The value of the cookie.

 * @type String

 *

 * @name $.cookie

 * @cat Plugins/Cookie

 * @author Klaus Hartl/klaus.hartl@stilbuero.de

 */

jQuery.cookie = function(name, value, options) {

    if (typeof value != 'undefined') { // name and value given, set cookie

        options = options || {};

        if (value === null) {

            value = '';

            options.expires = -1;

        }

        var expires = '';

        if (options.expires && (typeof options.expires == 'number' || options.expires.toUTCString)) {

            var date;

            if (typeof options.expires == 'number') {

                date = new Date();

                date.setTime(date.getTime() + (options.expires * 24 * 60 * 60 * 1000));

            } else {

                date = options.expires;

            }

            expires = '; expires=' + date.toUTCString(); // use expires attribute, max-age is not supported by IE

        }

        var path = options.path ? '; path=' + options.path : '';

        var domain = options.domain ? '; domain=' + options.domain : '';

        var secure = options.secure ? '; secure' : '';

        document.cookie = [name, '=', encodeURIComponent(value), expires, path, domain, secure].join('');

    } else { // only name given, get cookie

        var cookieValue = null;

        if (document.cookie && document.cookie != '') {

            var cookies = document.cookie.split(';');

            for (var i = 0; i < cookies.length; i++) {

                var cookie = jQuery.trim(cookies[i]);

                // Does this cookie string begin with the name we want?

                if (cookie.substring(0, name.length + 1) == (name + '=')) {

                    cookieValue = decodeURIComponent(cookie.substring(name.length + 1));

                    break;

                }

            }

        }

        return cookieValue;

    }

};