title: How to login website via scanning QR code?
body: <p>What I want to do is I want the users login to the account on their apps, after when they want to login on the web page, they can just scan the QR Code and automatically login the web page.</p>
  
  <p>Currently, I am using Xampp localhost to make my project. I only finished Login and Register web page using PHP.</p>
  
  <p>The problem is:</p>
  
  <p>1) I want to know how can I get the access token from server?</p>
  
  <p>2) How the server know when I scan the QR Code, that is the same person that want to login to the web page?</p>
  
  <p>3) Do I need to use OAuth2 to check from web page and apps the username or password is it match?</p>
  
  <p>I saw lot of example is about how Wechat just scan the QR Code then can login, but if I am using own application, how can I make it like Wechat?</p>