jQuery插件 — Cookie插件jquery.cookie.js 使用实例

Cookie是网站设计者放置在客户端的小文本文件。Cookie能为用户提供很多的使得，例如购物网站存储用户曾经浏览过的产品列表，或者门户网站记住用户喜欢选择浏览哪类新闻。 在用户允许的情况下，还可以存储用户的登录信息，使得用户在访问网站时不必每次都键入这些信息

使用方法：

引入jquery.cookie.js

<script src="scripts/jquery-1.6.4.js" type="text/javascript"></script>   <script src="scripts/jquery.cookie.js" type="text/javascript"></script>

使用方法

新添加一个会话 cookie

$.cookie('the_cookie', 'the_value');

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）”。

创建一个cookie并设置有效时间为 7天:

$.cookie('the_cookie', 'the_value', { expires: 7 });

注：当指明了cookie有效时间时，所创建的cookie被称为“持久 cookie （persistent  cookie）”。 

创建一个cookie并设置 cookie的有效路径：

$.cookie('the_cookie', 'the_value', { expires: 7, path: '/' });

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） 。 

读取cookie：

$.cookie('the_cookie'); // cookie存在 => 'the_value' $.cookie('not_existing'); // cookie不存在 => null

删除cookie，通过传递null作为cookie的值即可：

$.cookie('the_cookie', null);

将cookie写入文件

var COOKIE_NAME = 'username';       if( $.cookie(COOKIE_NAME) ){           $("#username").val(  $.cookie(COOKIE_NAME) );       }       $("#check").click(function(){           if(this.checked){               $.cookie(COOKIE_NAME, $("#username").val() , { path: '/', expires: 10, domain: 'jquery.com', secure: true });               //var date = new Date();               //date.setTime(date.getTime() + (3 * 24 * 60 * 60 * 1000)); //三天后的这个时候过期               //$.cookie(COOKIE_NAME, $("#username").val(), { path: '/', expires: date });           }else{               $.cookie(COOKIE_NAME, null, { path: '/' });  //删除cookie           }       });

参数设置

expires: (Number | Date)      有效期，可以设置一个整数作为有效期（单位：天），也可以设置一个日期对象作为Cookie的过期日期。如果指定日期为负数，那么此cookie将被删除；如果不设置或者设置为null，那么此cookie将被当作Session Cookie处理，并且在浏览器关闭后删除

path:  (String)          Cookie的路径属性，默认是创建该cookie的页面路径

domain: (String)     Cookie的域名属性，默认是创建该cookie的页面域名

secure: (Boolean)  如果设为true，那么此cookie的传输会要求一个安全协议，例如HTTPS

jquery.cookie.js

/**  * 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  *  */  /**  * Create a cookie with the given name and value and other optional parameters.  *  * @example $.cookie('the_cookie', 'the_value');  * @desc Set the value of a cookie.  * @example $.cookie('the_cookie', 'the_value', {expires: 7, path: '/', domain: 'jquery.com', secure: true});  * @desc Create a cookie with all available options.  * @example $.cookie('the_cookie', 'the_value');  * @desc Create a session cookie.  * @example $.cookie('the_cookie', null);  * @desc Delete a cookie by passing null as value.  *  * @param String name The name of the cookie.  * @param String value The value of the cookie.  * @param Object options An object literal containing key/value pairs to provide optional cookie attributes.  * @option Number|Date expires Either an integer specifying the expiration date from now on in days or a Date object.  *                             If a negative value is specified (e.g. a date in the past), the cookie will be deleted.  *                             If set to null or omitted, the cookie will be a session cookie and will not be retained  *                             when the the browser exits.  * @option String path The value of the path atribute of the cookie (default: path of page that created the cookie).  * @option String domain The value of the domain attribute of the cookie (default: domain of page that created the cookie).  * @option Boolean secure If true, the secure attribute of the cookie will be set and the cookie transmission will  *                        require a secure protocol (like HTTPS).  * @type undefined  *  * @name $.cookie  * @cat Plugins/Cookie  * @author Klaus Hartl/[email protected]  */  /**  * 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/[email protected]  */ 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;     } };