How to find out the id of the user who has visited the site (who has already been authorized in VKontakte)?

Question

In contact with

The task on the site is to track visitors who are already authorized on VKontakte.
That is, the visitor on my site does nothing, does not pass any authorizations. just looks at the site
and I will already know about it its id and, accordingly, the name
thanks
in php or javascript

Answer 1

Thanks for the link. There is a solution in the comments.
I want to write it myself, so questions :)
The script from the author of the topic on Habré, even though it requires actions from the user, after which only the name is issued
But there are definitely solutions, without any actions to get the username ... so I do a lot of "left" sites, with fake notifications from VKontakte
Me for peaceful purposes :)

Answer 2

habrahabr.ru/post/228617

Answer 3

Here it is described in detail: How to find out the vk id of visitors to your site ?

Answer 4

ru.soctracker.com
does a good job, the percentage of user detection is high compared to the rest + Facebook also supports mobile devices

Answer 5

I am also very interested in how the mechanism for determining a user ID without authorization works

Answer 6

We have been using this service for a couple of months now.
I'm glad it's free.
traffgui.com