XML getText возвращает ноль - Android

Веб-страница взаимодействует с расширением через фоновый скрипт.

manifest.json:

"background": {
    "scripts": ["background.js"],
    "persistent": true
},
"externally_connectable": {
    "matches": ["*://(domain.ext)/*"]
},

background.js:
chrome.runtime.onMessageExternal.addListener(function(msg, sender, sendResponse) {
    if ((msg.action == "id") && (msg.value == id))
    {
        sendResponse({id : id});
    }
});

page.html:

<script>
var id = "some_ext_id";
chrome.runtime.sendMessage(id, {action: "id", value : id}, function(response) {
    if(response && (response.id == id)) //extension installed
    {
        console.log(response);
    }
    else //extension not installed
    {
        console.log("Please consider installig extension");
    }

});
</script>