I have a function and created a global variable.
The alert inside the function is alerting the result as expected but the variable is showing nothing.
How can I fix this?
Here's the code:
var connectionResult = '';
function checkConnection() {
var networkState = navigator.connection.type;
var states = {};
states[Connection.UNKNOWN] = 'Unknown connection';
states[Connection.ETHERNET] = 'Ethernet connection';
states[Connection.WIFI] = 'WiFi connection';
states[Connection.CELL_2G] = 'Cell 2G connection';
states[Connection.CELL_3G] = 'Cell 3G connection';
states[Connection.CELL_4G] = 'Cell 4G connection';
states[Connection.CELL] = 'Cell generic connection';
states[Connection.NONE] = 'No network connection';
alert('Connection type: ' + states[networkState]);
var connectionResult = states[networkState];
};
checkConnection();
alert(connectionResult); // Returns Nothing
The problem is that you are creating a local variable named connectionResult in the checkConnection rather than assigning to the global connectionResult.
Replace
var connectionResult = states[networkState];
with
connectionResult = states[networkState];
And it will work.
To expand on TJ Crowder's comment below, you can make this function a little more efficient, since you are declaring what is essentially a constant over and over again. You can change the code as follows:
var NetworkStates = {}; // this never changed in the old function, so refactored it out as a "constant"
NetworkStates[Connection.UNKNOWN] = 'Unknown connection';
NetworkStates[Connection.ETHERNET] = 'Ethernet connection';
NetworkStates[Connection.WIFI] = 'WiFi connection';
NetworkStates[Connection.CELL_2G] = 'Cell 2G connection';
NetworkStates[Connection.CELL_3G] = 'Cell 3G connection';
NetworkStates[Connection.CELL_4G] = 'Cell 4G connection';
NetworkStates[Connection.CELL] = 'Cell generic connection';
NetworkStates[Connection.NONE] = 'No network connection';
function getConnectionState() {
return NetworkStates[navigator.connection.type];
}
Now wherever you need the connection state you can just call getConnectionState rather than having a global variable floating around.
var connectionResult
inside checkConnection
creates a new variable called connectionResult
.
This "inner" variable is only in scope inside checkConnection
. It hides, or "shadows" the one that you intend to use: any reference to connectionResult
inside checkConnection
uses it instead of the "outer" variable that you expect.
Just remove var
and you'll use the existing connectResult
:
connectionResult = states[networkState];
var connectionResult = states[networkState];
creates a new variable connectionResult
within the scope of the function which is completly unrelated to the global variable connectionResult
Just use
connectionResult = states[networkState];
in order to assign the network state to the global variable
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