I succeeded in setting cookies. After refreshing the page again, the cookies I set were gone.

  ios, question

The code is as follows:

header("Content-type: text/html;   charset=utf-8");
 if (isset($_COOKIE['test']))
 bracket
 Cookies obtained by echo' are:'. $_COOKIE['test'];
 bracket
 Elseif (setcookie ('test',' okh', time () plus 3600, '/', '.us.com'))
 bracket
 Echo' set cookies:test';
 bracket
 Else
 bracket
 Echo' nothing';
 bracket

Using us.com to access, the above code has been successfully set under chrome, but it has not been recorded.
Looking for the reason for half a day, a friend told me from the manual:

The domain that the cookie is available to. Setting the domain to
‘www.example.com’ will make the cookie available in the www subdomain
and higher subdomains. Cookies available to a lower domain, such as
‘example.com’ will be available to higher subdomains, such as
‘www.example.com’. Older browsers still implementing the deprecated »
RFC 2109 may require a leading . to match all subdomains.

So I made such an adjustment:

  1. Visit with www.us.com
  2. The code before modification was

    Setcookie(‘test’, ‘okh’, time () plus 3600, ‘/’, ‘www.us.com’)

This is the normal setting and normal recording.

But there are two problems:

  1. How do I set cookies for domain names without WWW? For example: us.com
  2. Although www.us.com can be used under www.us.com, it cannot be used under us.com. How to set cookies to make them universal?

PS: I know that the parameter domian can be successfully set, but my requirement is to set cookies under different domains, not just under one domain name, so I still hope to keep this parameter, and it is better to set such parameters as:.us.com

This domain name is special. Firefox does not thinkwww.us.comYesus.comSecond-level domain of:

var eTLDService = Components.classes["@mozilla.org/network/effective-tld-service;  1"]
 .getService(Components.interfaces.nsIEffectiveTLDService);
 
 eTLDService.getBaseDomain(gBrowser.selectedTab.linkedBrowser.currentURI);
 /*
 www.us.com
 */

us.comIneffective_tld_names.datThe document lists:

// CentralNic :  http://www.centralnic.com/names/domains
 // Requested by registry  <gavin.brown@centralnic.com > 2012-09-27
 ae.org
 ar.com
 br.com
 cn.com
 com.de
 de.com
 eu.com
 gb.com
 gb.net
 gr.com
 hu.com
 hu.net
 jp.net
 jpn.com
 kr.com
 no.com
 qc.com
 ru.com
 sa.com
 se.com
 se.net
 uk.com
 uk.net
 us.com
 us.org
 uy.com
 za.com