page.js

window.chrome = (function () {
    return window.msBrowser ||
        window.browser ||
        window.chrome;
})();

//var runtimeOrExtension = chrome.runtime && chrome.runtime.sendMessage ? 'runtime' : 'extension';

var inoLastResult = {};

function get_client_counters(force){
    if (!document.getElementById('total_unread_cnt')){
        if(chrome.runtime && chrome.runtime.sendMessage){
            chrome.runtime.sendMessage(0);
        }
        return;
    }
    var result = {
        "unread_cnt" : parseInt(document.getElementById('total_unread_cnt').innerHTML),
        "logged_in" : parseInt(document.getElementById('logged_in_div').innerHTML),
        "unseen_cnt" : parseInt(document.getElementById('total_unseen_cnt').innerHTML),
        "max_cnt" : parseInt(document.getElementById('max_unread_cnt').innerHTML)
    };
    if(force == false && result.unread_cnt == inoLastResult.unread_cnt && result.unseen_cnt == inoLastResult.unseen_cnt){
        return;
    }
    inoLastResult = result;
    if(chrome.runtime && chrome.runtime.sendMessage){
        chrome.runtime.sendMessage(result);
    }
}

UpdateTimer = setInterval(function(){
   get_client_counters(false);
}, 1000);


chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
    if(request.action == 'force_counter_refresh'){
        get_client_counters(true);
    }
});

if(!document.getElementById('inoreader_companion_div')){
    var dummy = document.createElement("a");
    dummy.id = 'inoreader_companion_div';
    document.body.appendChild(dummy);
}

window.addEventListener("message", function(event) {
    if(event.source != window){
        return;
    }
    if(event.data.request){
        try{
            chrome.runtime.sendMessage(event.data.request);
        }catch(e){
        }
    }
}, false);