So you are using cookies on your website, but when a visitor visits www.yourdomain.com and yourdomain.com the cookie doesn’t get set across both! That is because in essence, www. is simply a subdomain. The “www” component is not a protocol, it is not necessary, instead all it is, is just a marketing ploy. But anyway. Here is what you would do normally:
setcookie('YourCookieName', 'Some Values', time() + 3600, '/', 'mydomain.com');
Damn! Almost there! The part you are missing to add a cookie irrespective of the subdomain is “.mydomain.com”. Yep, just add a . infront of your domain name. So you would have:
setcookie('YourCookieName', 'Some Values', time() + 3600, '/', '.mydomain.com');
All done ^^ Enjoy




Comments About HowTo: Get Cookies Across Subdomains PHP
// 6 comments so far.
Aaron // June 25th 2008
Thanks!
Kenneth // October 31st 2008
Nice tutorial
Biily Bob // April 23rd 2009
Great tut, straight to the point. Good work.
SpYeR // October 29th 2009
Thanks. Very useful for sites with blogs.mydomain.com, news.mydomain.com etc.
khal3d // December 12th 2009
what about session?
VoiDeT // December 12th 2009
ini_set(’session.cookie_domain’, ‘.whatever.com’); should do the trick
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