background.js

var currentTab;
var currentState;

/*
 * Enable or disable Debugging
 */
function toggleButton(event) {
    console.log('toggleButton');
    console.log(typeof event);
    console.log(event);

    function onExecuted(result) {
        browser.tabs.executeScript(
            currentTab.id, {
                file: "cookies.js"
            });
    }

    function onError(error) {
        console.log(`Can't execute script: ${error}, for current tab ID ` + currentTab.id);
    }

    var userTriggered = typeof event === 'object';
    var executing = browser.tabs.executeScript(
        currentTab.id, {
            code: "var currentState = "+ currentState +"; var userTriggered = " + userTriggered + ";"
        });
    executing.then(onExecuted, onError);
}

browser.browserAction.onClicked.addListener(toggleButton);

/*
 * Switches currentTab to reflect the currently active tab
 */
function updateActiveTab(e) {
    console.log('Event', e);
    function isSupportedProtocol(urlString) {
        var supportedProtocols = ["https:", "http:", "ftp:", "file:"];
        var url = document.createElement('a');
        url.href = urlString;
        return supportedProtocols.indexOf(url.protocol) != -1;
    }

    function updateTab(tabs) {
        if (tabs[0]) {
            currentTab = tabs[0];
            console.log('Current tab is ' + currentTab.id);
            if (isSupportedProtocol(currentTab.url)) {
                toggleButton();
            }
        }
    }

    var gettingActiveTab = browser.tabs.query({active: true, currentWindow: true});
    gettingActiveTab.then(updateTab);

}

function updateButton(result) {
    if (typeof currentTab.id === 'undefined') {
        console.log('No current tab yet')
        return;
    }

    browser.browserAction.setIcon({
        path: result ? {
            32: "data/icons/debug_32_active.png",
            48: "data/icons/debug_32_active.png"
        } : {
            32: "data/icons/debug_48_inactive.png",
            48: "data/icons/debug_48_inactive.png"
        },
        tabId: currentTab.id
    });

    browser.browserAction.setTitle({
        title: result ? 'Disable Debugging' : 'Enable Debugging',
        tabId: currentTab.id
    });
}

// listen to tab URL changes
browser.tabs.onUpdated.addListener(updateActiveTab);

// listen to tab switching
browser.tabs.onActivated.addListener(updateActiveTab);

// listen for window switching
browser.windows.onFocusChanged.addListener(updateActiveTab);

// Listen to button clicks
//browser.browserAction.onClicked.addListener(updateActiveTab);

function notify(message) {
    console.log(message);
    if (typeof message.state !== 'undefined') {
        updateButton(message.state);
        currentState = message.state;
    }
}

// Listen to content scripts messages
browser.runtime.onMessage.addListener(notify);

// update when the extension loads initially
updateActiveTab();