auto-refresh/src/static/js/background.js

(function() {
    var _timers = {};
    var timers = {
        get: function(id) {
            return _timers[id] || false;
        },
        set: function(tab, interval) {
            var id = tab.id;
            
            (_timers[id]) && timers.remove(tab.id);
            _timers[id] = {
                tab: tab,
                nextRefresh: (new Date).getTime() + interval,
                interval: interval,
                timer: timers.start(id, interval)
            };
        },
        remove:  function(id) {
            if(_timers[id]) {
                chrome.browserAction.setBadgeText({tabId: id, text: ''});
                clearInterval(_timers[id].timer);//不定时刷新
                delete _timers[id];
            }
        },
        start: function(id, interval) {
            return setInterval(function() {
                if(_timers[id] && (new Date).getTime() >= _timers[id].nextRefresh) {
                    chrome.tabs.reload(id, function() {
                        setTimeout(function() {
                            _timers[id].nextRefresh = (new Date).getTime() + _timers[id].interval + 999;
                        }, 1);
                    });   
                } else if(_timers[id]) {
                    var timeLeft = moment(_timers[id].nextRefresh - (new Date).getTime());
                        
                    chrome.browserAction.setBadgeText({tabId: id, text: '' + timeLeft.format('m:ss')});
                } else {
                    timers.remove(id);
                }
            }, 500);
        }
    };
    
    // Set timers on the window object so we can access it from the popdown
    window.timers = timers;
    
})();