I have an old asp.net webform website. I am integrating Google login to enable the users to log in with their Google credentials apart from their standard credentials (username and password).

I have used Nemiro.Oauth library and everything is implemented absolutely fine. The issue is that I either need to use postback on the page or use a popup window to allow the user Login with their Google credentials. Is there any library or way to go social authentication using Ajax? Does Google provide API to achieve this? I understand that this involves redirecting to the Google site for authentication but maybe there is some way that I have not come across to do this using AJax. I will need to add more external login like LinkedIn, Twitter, etc.