Getting the page events, tab closed, lost focus?

Question

The question is how to query such events on specific tab:

• User has loaded the tab with specific URL like: google.com (I think the easiest way to do this is to use

Answer 1

You cannot register a listener for such events on a specific tab. There are different approaches possible, but I suggest using chrome.tabs.* events to listen for events regarding all tabs and then do the filtering manually.

[Note: You will need to request the necessary permissions in your manifest, e.g. "tabs", "idle", the host match patterns etc.]

---

User has loaded the tab with specific URL like: google.com

Attach listeners for the followig events:

• chrome.tabs.onCreated
• chrome.tabs.onUpdated

...and then filter based on the URL. E.g.:

var urlRegex = /https?:\/\/([^\.]+\.)?google.com/;
chrome.tabs.onUpdated.addListener(function(tabId, info, tab) {
    if (info.url && urlRegex.test(info.url)) {
        /* The tab with ID `tabId` has been updated to a URL
         * in the `google.com` domain. Let's do something... */
        ... 
    }
});

---

User has closed the tab.

Attach listeners for the followig events:

• chrome.tabs.onRemoved

...and then filter based on the URL. E.g.:

var urlRegex = ...;
chrome.tabs.onRemoved.addListener(function(tabId, info) {
    chrome.tabs.get(tabId, function(tab) {
        if (urlRegex.test(tab.url)) {
            /* The tab with ID `tabId`, with a web-page in the
             * `google.com` domain, is being closed. Let's do something... */
            ... 
        }
    });
});

---

The tab is inactive, like switching to another tab.

Unfortunately, there is no onFocusLost event. You could listen for the chrome.tabs.onActivated event and keep track of the active tab in each window. Then when another tab is activated, do something if the previously activated was pointing to google.com. (I am not going to describe a mechanism in detail).
For this particular case, it might be simpler to use a content script and notify your background page when the tab is deactivated:

 /* In `content.js` */
 window.addEventListener("blur", function() {
     chrome.runtime.sendMessage({ text: "focusLost" });
 })

/* In `background.js` */
chrome.runtime.onMessage.addListener(function(msg, sender) {
    if (msg.text === "focusLost") {
        /* OMG - The user switched to another tab :( */
    }
});

---

Check if the user is idle or not.

You cannot check if the user is inactive in regard of a specific tab, but in general. As you mentioned you can use the chrome.idle API, registering a listener for the chrome.idle.onStateChanged event.

chrome.idle.onStateChanged.addListener(function(newState) {
    if (newState == "active") {
        /* The user came back. Let's do something... */
    } else {
        /* The user is not around. Let's wait... */
    }
});