Where can I get a free jabber client for the site?

Question

Messengers

I'm creating a wordpress site while on Denver apache on my computer. I want to make a support service through a free jabber client.
Ideally, there should be a mini window with the ability to send and receive text messages (and maybe files or calls and nothing more than a one-on-one conversation). Receive and send messages to the site also through the jabber client on your smartphone.
Registration of new participants in the conversation is not needed (so that they only enter their email for correspondence instead of jid), although if there is registration, then at least it is.
But!
The jabber server itself should not be on my server, but for example the jabber.ru server.
To connect through a third-party server.
In general, a free chat through jabber on your site one-on-one and that the jabber server was someone else's.
How to implement it?
Desirable in detail.

Answer 1

Candy . Clings easily to http(s)://jabber.ru/http-bind ; except that it will be necessary to intercept the message about the need to enter captcha, and process it in some way.

Answer 2

For such purposes, https://core.telegram.org/bots/api is better suited

Answer 3

https://www.google.com.ua/search?q=js+jabber+client