Facebook chat on mobile?

[♥]

So on the side bar of the Facebook chat, there's usually a time next to a person's mobile icon, like "4h".

What does it mean if it DOESN'T have the time next to it, but the mobile icon is still there?

[wittyactivity615]

If the time is shown it means the user is online with their phone, but they haven't done anything on facebook since that amount of time. So if it shows "4h", that means they've been idle for 4 hours.

If there's no time shown, it means they have done something within the last few minutes.

And if it's just a green dot, that means they're on Facebook's normal website, probably from a computer.