I'm having a html page “menu.html” which allows users to open different other html pages based on their profile and rights via simple button clicks. In menu.html, User ID and password is checked via Ajax/PHP. In PHP .htpasswd is adapted with the user ID and session ID (or password) accordingly to remain secure. User ID and session ID (or password) are returned to javascript.
Today the redirections within menu.html finds place via window.open as follows:

window.open("https://"+user-id+":"+session-password+"@xyz.be/example1.html)

It all works fine. Menu.html is handling the security aspects of many other HTML files.

Unfortunately including credentials in the url (user-id+":"+session-password@) is now depreciated.

What is the best way to redirect to a HTML page while providing the credentials? All finds place on the same server.

Many thx Pierre