Interested in the following:
For example, I just went to the site without logging in. It is necessary at that time, while I am on the site, to issue an
alert(0) , and if I’ve already left the site and then returned after n minutes / hours, I didn’t give out more.
Or easier. Vkontakte black windows come out when the user is on the site, and if he already left and then came, they do not get out.
Tell me how to approach this task?