XSS and escaping?

Question

Perl

Where is it better to do screening on the client, or on the server?
Of course, I am convinced that the server should do this, since it is more adapted to this, has a bunch of all sorts of methods. And on the client, you need to monitor data entry and spend time processing string information.
Share your experience.

Answer 1

The client cannot be trusted! Only on the server.

Answer 2

If html is formed on the server, then escaping is on the server.
If it is formed on the client, then it is screened within the framework of json (or in what it comes from the server), and html-screening can be performed by a javascript template engine.
And more, I did not understand, and here perl.