Php question on putting a chat on or off

I have a website and I would like to give the users an option to load or not load a php chat.

My main page is index.php.

On this page, I have a variable called $location.

it will load home.php in the middle part of the page.

If you go to mysite.com/index.php?location=about.php

about.php will load in the middle part of the page.

Now, I also have a shout.php page. For now, it loads automaticly in the main page, in an iframe for it.
I would like to change it.

At the place of the chat, I want to only have a link:

Click here to Enable Chat.

And if users click on this link, the chat loads as it's loading now, on the main page. Under the chat, they'll have a link that says:

Disable chat

and if they click, the original page with the Click Here to Enable Chat will appear.

How do I do it?

Uh, just make two pages?

One with the enable one. When they click it, takes them to a page with the chat and a disable link, which goes back to the page with the enable link.

No.
Not the entire page is with the chat!
Only a part of the main page.

The main page includes many other pages with include() functions.
These includes are included in tables.

One of the tables include shout.php.

I want to disable and enable this page.

How would I make it in php or to load it in the iframe?