在firefox 和chrome下用script 调用setcookie页面可能轻松实玩跨域cookie设置，可在ie下就不行了，幸好可以通过设置p3p头信息实现。
首先：创建 a_setcookie.php 文件，内容如下：
然后：创建 a_getcookie.php 文件，内容如下：
最后：创建 b_setcookie.php 文件，内容如下：
P3P Header is present:
CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR"
Compact Policy token is present. A trailing 'o' means opt-out, a trailing 'i' means opt-in.
Information is used to complete the activity for which it was provided.
Information may be used for the technical support of the Web site and its computer system.
Information may be used to enhance, evaluate, or otherwise review the site, service, product, or market.
Information may be used to create or build a record of a particular individual or computer that is tied to a pseudonymous identifier, without tying identified data (such as name, address, phone number, or email address) to the record. This profile will be used to determine the habits, interests, or other characteristics of individuals for purpose of research, analysis and reporting, but it will not be used to attempt to identify specific individuals.
Information may be used to create or build a record of a particular individual or computer that is tied to a pseudonymous identifier, without tying identified data (such as name, address, phone number, or email address) to the record. This profile will be used to determine the habits, interests, or other characteristics of individuals to make a decision that directly affects that individual, but it will not be used to attempt to identify specific individuals.
We share information with ourselves and/or entities acting as our agents or entities for whom we are acting as an agent.
Non-financial identifiers, excluding government-issued identifiers, issued for purposes of consistently identifying or recognizing the individual. These include identifiers issued by a Web site or service.
Information actively generated by the purchase of a product or service, including information about the method of payment.
Data actively generated from or reflecting explicit interactions with a service provider through its site -- such as queries to a search engine, or logs of account activity.
Data about an individual's characteristics -- such as gender, age, and income.
Mechanisms for maintaining a stateful session with a user or automatically recognizing users who have visited a particular site or accessed particular content previously -- such as HTTP cookies.
Data about an individual's likes and dislikes -- such as favorite color or musical tastes.
Information about the computer system that the individual is using to access the network -- such as the IP number, domain name, browser type or operating system.
Data passively generated by browsing the Web site -- such as which pages are visited, and how long users stay on each page.
Other types of data not captured by the above definitions.
Web Site does not collected identified data.
Validate at: http://www.w3.org/P3P/validator.html
Learn more at: http://www.fiddlertool.com/redir/?id=p3pinfo