Login form and modal right in the browser (probably in PHP). How to do this?

Question

User identification

When you visit some sites directly in the browser , a pop-up window appears with information (in the case of fraudulent sites, it sometimes also prevents you from closing the tab!) Or with a primitive authorization form - username and password. It is important that such a window is not an element of the site's interface; its design corresponds to the interface of the browser itself. For clarity, I will attach screenshots:

Apparently, such a window is made in PHP.
Accordingly, the question is: how to do this? Though with the form of authorization, though with the text.
And the second question is whether such windows have some kind of their own name, which would allow not to describe it, as I described, but to immediately distinguish it from, for example, pop-up forms on the site.

Answer 1

In the case of authentication, this is Basic Auth, it is implemented by means not of PHP, but is done on Apache or Nginx
. In the case of text, this is JS,
for example
alert('Какой-то текст');

Answer 2

It seems like this is a function on hostings
. It's called "Directory Privacy", if I'm not mistaken.
It simply sets a password to access a folder on the site.
Example: gamesense.epizy.com/toster (Username: 1, password: 1)

Answer 3

https://secure.php.net/manual/ru/features.http-auth.php
text - realm parameter content.