Cookies - set across multiple domains

Question

My company has a setup as follows:

• subdomain1.domain1.com
• subdomain2.domain1.com
• subdomain3.domain1.com
• subdomain4.domain1.com

Answer 1

This answer is a slightly different version of my answer on the question "Set cookie on multiple domains with PHP or JavaScript".

Do what Google is doing. Create a PHP (or any other server language file) file that sets the cookie on all 3 domains. Then on the domain where the login is going to be set, create a HTML file that would load the PHP file that sets cookie on the other 2 domains. Example:

 
 
 Please wait..........
 
 
 

Then add an onload callback on body tag. The document will only load when the images completely load that is when cookies are set on the other 2 domains. Onload Callback :

Now cookies are set on the three domains.

Source