chrome.app.runtime.onLaunched.addListener(function() { chrome.app.window.create('main.html', { frame: 'chrome', id: 'main-window', minWidth: 960, maxWidth: 960, minHeight: 600, maxHeight: 600 }, function(window_child) { window_child.onClosed.addListener(function() { // connectionId is passed from the script side through the chrome.runtime.getBackgroundPage refference // allowing us to automatically close the port when application shut down if (connectionId != -1) { chrome.serial.close(connectionId, function() { console.log('CLEANUP: Connection to serial port was opened after application closed, closing the connection.'); }); } }); }); });