php - How do you enable customers to log in to your site using their Google account? -

I just watched Does it use Google Accounts, Yahoo, and everyone to sign in to your site? Can i do this

I mean, customers do not need to register on my site, they can only sign in with their accounts on the above sites.

If you have a solution, then I like a PHP and MySQL based choice.

see here.

Also be sure to mention it for more information.