onLine property
Returns the online status of the browser. The property returns a boolean
value, with
true meaning online and false meaning offline. The property
sends updates whenever the browser's ability to connect to the network
changes. The
update occurs when the user follows links or when a script requests a
remote page. For
example, the property should return false when users click links soon
after
they lose internet connection.
Browsers implement this property differently.
In Chrome and Safari, if the browser is not able to connect to a local
area network
(LAN) or a router, it is offline; all other conditions return true. So
while you can assume that the browser is offline when it returns a false
value, you cannot assume that a true value necessarily means that the
browser can access
the internet. You could be getting false positives, such as in cases where
the computer
is running a virtualization software that has virtual ethernet adapters
that are always
"connected." Therefore, if you really want to determine the online status
of the
browser, you should develop additional means for checking.
In Firefox, switching the browser to offline mode sends a false value.
Until Firefox
41, all other conditions returned a true value; testing actual behavior
on Nightly 68 on
Windows shows that it only looks for LAN connection like Chrome and Safari
giving false
positives.
You can see changes in the network state by listening to the
online
and
offline
events.
Implementation
external bool get onLine;