header('P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR"');可以发送这样子的头。这里有个例子http://hi.baidu.com/thinkinginlamp/blog/item/5e2a02084f1dafd163d9865f.html
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header('P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR"'); setcookie("test", $_GET['id'], time()+3600, "/", ".a.com");
在 setcookie 之前加上 P3P header,可以解决cookie跨域问题 ......