how to know if user online on facebook mobile or on computer?

[♪£yricảl♪]

I saw that small mobile icon beside the friend's name on the sidebar, besides the icon is the time in which the user last online at (in hrs/mins) how to know if friend is using facebook mobile or online using computer? Lets say, the time besides the mobile icon is 1hr, i saw my friend online just now and he offline, the time is still 1hr, does that mean he online using computer??
i dont want to try that... is there any other way to find out?
i heard from my friend that even if theres a green dot, the user might be using mobile too... is that really true?

[Komal]

One way there is you can find out is by sending him her a message. And HOPEFULLY if they reply, right below what they sent... You will see a "Sent from web" or either "Sent from Messenger" or something.

[MAUDE STONER]

a green dot says they are online using their computer.
a icon of a phone is saying they are using phone.
refresh your page and you will see if they are truly online.
though sometimes they may not be online. I appear to be online
but i am outside doing yard work.
depends on the person

[Daniel]

If The Green Dot is Displayed that Means they are Online It Could be On Either PC Or Mobile If There Signed onto There Phone and Not Using Chat Right Now the Mobile Icon will Appear on the Chat List

[marti]

They are only online if it is green