Remembering the user after logging into the google api system (when the user is "updated" or goes to another page on my site)

Question

I need help with signin google api. I have a Google login button on my site. (using their API- (function () {var po = document.createElement ('script'); po.type = 'text / javascript'; po.async = true; po.src = ' https://apis.google .com / js / client: plusone.js '; var s = document.getElementsByTagName ('script') [0]; s.parentNode.insertBefore (po, s);}) ();)

HOWEVER, when I refresh a page or go to another page, it shows me a login button, and I need to login again. How can I “remember” a user after the first login, even after updating? (on facebook it's easy - using FB.getLoginStatus (updateStatusCallback);) thanks!