How to transfer registration information and automatically register on another site when a user clicks on a link?

The safest way is to use Single Sign On via SAML.

You have to use token-based security, i.e. when the user enters their credentials on website A, then website A returns an access token, and then using that token, you can verify the user on both sites, i.e. send an access token with every request.

Basically, the way social site accounting works, they also provide an access token and this is called the auth protocol.

You can send via AJAX the authentication data from website "A" to Internet "B" when you click the "Read more" button: after that, you check the correctness of these data. If so redirect to page "B" (you can do it with ajax response)

   $.ajax({
        type: 'post',
        url: 'b.php',
        data: userauth,
        error: function(errors) {
            console.error(errors);
        },
        complete: function(data) {
            if(data=="correct"){ /*redirect*/ }else{ /*nothing*/ }
        }
    });

      

        
        
        
      

    

I think it would be an option ...

Hello!

The best way I would like to suggest:

1: every time the user logs into the view id, now the user is generated below the table structure

uname | password | seesion id     | user ip address  |isloogenid
a      pwd1      sessionidcreated  user looged in ip

      

        
        
        
      

    

- all parameters are the same login in the user, otherwise no

$seesionifdromdb
$ipfromdb
$userloggedinfromdb

$currentipwheresiteisopened
$valeofphpsessionif

if(($seesionifdromdb == $valeofphpsessionif) && ($ipfromdb == $currentipwheresiteisopened) && ($userloggedinfromdb==1)){
    // here start session neede to make user logged in
}

      

        
        
        
      

    

As per your situation allows you to have a logical view. sites: "Site A", "Site B"

Let's have a common input stream. If a user visits Site A or Site B, then a session will be created for that user with some session id and some custom session variables that you configure to have the user logged in throughout the entire website.

eg: $_SESSION['user_id'] = {some id from database};
    $_SESSION['prefered_language_code']='eng';
    $_SESSION['user_name'] = 'abc';

      

        
        
        
      

    

Then you biapasing the login process until these variables are available in the session

eg:function checkSession(){
            if($_SESSION['user_id']!=''){
                 return true;}
            else{return false;}
     }
    on the other pages of both website
  if(checkSession()){
     return true;
  }else{
  //send to login page of website A or Website B respectively;
  }

      

        
        
        
      

    

Something like this function that you use to check user access for the rest of the web pages. When it logs out, you have to destroy this session variable.

So now the answer to your question is: 1) Since you are managing two websites and according to your comment, that is, "Now I want to skip the 'Login' process from website B (since this user is already registered with A)" , this means that in both cases the login credentials must be the same.Now the solution is to achieve the desired situation, you must follow the same login process with the same session variables (only those used to check the login status user) and the login to login to the website, that is, "site A and website B".

They then appear to be two different websites, but logically work as one since they use a login session variable. This means that if a user visits one site, then logically he goes through the process of logging into another website.

2) You can set the type of login field in the database to keep track of user login

 eg:loggin_token; comment some uniquely generated key or login_key

      

        
        
        
      

    

and sets them with some session variable

You can now check the session for the session variable to keep the login check on both sites

Hope this helps as this is the easiest way to manage these

Ignore any recommendation to send a password.

Lix's answer with a one-time token is a valid approach. If you don't want to worry about implementation, you might be interested in existing one-shot deployments .