I don't know if this is the best section to ( ask questions ). So, excuse me.

It's my first topic anyway, and I couldn't find any other section to ask for help.

I believe you don't need any explanation about my problem, but here it is anyway:

E.g :
John just started a topic at a.html, while Sandra navigates b.html,

I want some solutions to let Sandra knows about John's topic at once.

Could that be happen?

Notice: We're talking about 2 different pages at the same directory in some site.

Any help will be approciated!

I mean please help me !!