Local storage with sso

Hi, I am working with discourse 2.0 and I using perfectly sso with my own site for discourse, I just have a problem, I need send some information to discourse from my site and I trying save this information in local storage in my site but when I change to the my discourse site the information that I had saved in the local storage disappear and the local storage only contain information about the discourse, I think that is because discourse run in a container of docker and dont share the same environment or similar with the local storage of my site, so I trying with the cookies but is so hard get the cookies form another domain so I don’t know how I can do this, send some information between my site to discourse, this information is a token that I need to do some validation, and I have to use to do a petition from a script that I am using in the discourse