results = DBArray("SELECT Member_id FROM online WHERE txtActivity = '<b>Chat Room</b>'")

UsersCurrentlyInChat = "#"
for x = 0 to UBound(results,2)
    UsersCurrentlyInChat = UsersCurrentlyInChat & results(0,x) & "#"
next

results = nothing

function isUserInChat(userid)
    isUserInChat = false
    If InStr(UsersCurrentlyInChat,userid) Then isUserInChat = true
end function

If isUserInChat(3) Then
    echo "YES"
Else
    echo "no"
End If

If isUserInChat(1959) Then
    echo "YES"
Else
    echo "NO"
End If