why ppl appear offline in facebook chat list as soon as I click them.?

[Saleha f]

as soon as I click on the person whose online in the chat box ,they appear offline...even if they are idle or online....

 

[Jessica.]

Sometimes it takes a while for it to update, so when you click on it, it refreshes and they are usually offline then.

 

[Not as Naive as I Look]

the chat feature is not real time, meaning, it takes time to update who is offline or online. when you go online, your friends take a while until they see that you are online, and same when you go offline. there is a lag time until you disappear from the chat list.