access the sources or console window object or events - google-chrome-extension

I'm building a chrome extension and I would like to be able to access the sources of console window objects, or possible be able to listen to their events. I want to know when the user makes changes to either of these and get information about the change. I spend some time in the API docs and it looks like this isn't possible, but thought I would ask just in case I'm missing something.

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Direct access to Chrome's Extension API

Is there any way how to access the Chrome's extension API directly? What I mean is e.g. something like the Developer's Console for JavaScript, or even javascript: in the URL.
I ask because creating an extension sounds like A LOT of additional work, given that I have never created any. (especially once more advanced permissions [Tabs] get involved).

Struggling with Chrome Extension architecture

I'm new to Chrome extension development, and I'm a bit struggling with the architecture to put in place.
I would like to develop an extension (browser_action), that, when the button is clicked, opens a window where information will be populated from the WebTraffic.
I figured out I could use the WebRequest API to get info about the traffic.
I could create a popup window, but it's displayed only when I click on the extension button, and hides as soon as I click somewhere else
I tried creating a background window, but it does not show up.
I'd be very grateful if anyone could help me with the initial setup of my application.
Thanks in advance
You need both.
Take a look at the Architecture Overview, or maybe this question.
The lifetime of the popup is indeed equal to how long it stays on screen. It's the UI part, but putting logic there is usually bad.
A background page is permanently there but invisible. It's typically the "brain" of an extension, taking care of heavy lifting and routing messages to other parts.
In short:
You need a background script to collect webRequest information for you in some format.
You need a popup page to show it. Keep in mind it's not guaranteed to be present at a given time and can close at any time.
It's probably best to use Messaging to request the information from the background page. If you need real-time updates, you can use long-lived connections.
In your case you can also tightly couple the two and call chrome.runtime.getBackgroundPage() to directly reference stuff in it.

Show balloon notification with latest change log entries on update

I would like to display the latest top 3-5 entries of my extension change log (TXT file) when it's auto-updated and ideally in a balloon-type event like the one when you have successfully installed an extension. It should show/popup near the wrench-icon area. Like a replacement for #history that GM scripts have.
There are already a few SO questions about how to get extension version like here.
There are also one here to detect if it's an install or update based on version.
It is not desktop notifications I want.
My question is how to make the balloon and populate it with the lines.
An alternative is open my options.html page in a new tab and show the change log entries there somehow. Requires tabs permission in the manifest.json file.
chrome.tabs.create({url:chrome.extension.getURL('options.html')});
Any ideas how to do this?
Or is this impossible to do?
There's neither a mechanism to create a "balloon" notification (that's reserved for native Chrome code), nor to pop out the popup without user interaction. Your automatic notification methods are fairly limited: creating a new tab with a changelog is certainly possible, but not particularly user-friendly (since it will simply open at some arbitrary time, completely remote from the user's intent).
If possible, I'd suggest waiting to notify the user until she interacts in some way with the extension. Clicking on a page-action, for instance, could have some sort of infobar-like note at the top of the popup's UI inviting the user to read more about the update.

What general approach can I take to parse the contents of a website?

Say someone else has a website generated by JavaScript, so I can't go look at the source and read what should be on the screen. How can I grab the text on the screen so I can feed it into another program? Also, how can I write a program that automatically clicks on radio buttons, links, etc. that satisfy certain criteria?
You can write a web scraping tool in Perl or Python. Or, you can use existing tools and frameworks to achieve that.
Check out Scrapy, an open-source tool written in Python.
Take a look at Selenium too.
To parse dynamic content you could see the javascript source and get that same content the same way the webpage is getting it. (ie. replicating ajax calls and such)
If you want to submit data (not actually click on the elements) as if it were clicked/edited/selected you could also send a request containing the same data that the server is expecting by using some HTTP library, like CURL. See an example here.
If you need to handle content generated by script, then your first problem is to cause the script to execute. Further, the script will want to generate the content into a DOM. That means you need to have a DOM, and a script engine, and probably HTTP access to the Internet, and XML handling, etc.
If that sounds a lot like a web browser, then you're listening.
What you basically need is a web browser that you can control from a program. You'll need to be able to tell it to browse to a page, click buttons and links, etc., then you'll need to read back the resulting DOM.
Only then will you need to parse the page.
If you're in the Microsoft world, then you can use the WebBrowser control. There are several forms of this, and they all amount to the same thing: you can have Internet Explorer run inside of your program, and your program can control it.
I understand there are other browsers that can be controlled from a program, but since I don't know their details, I'll wait for someone else to tell us both.

Tracking a Chrome extension's version with Google Analytics custom variables

So I have a Chrome extension which uses Google Analytics for tracking various things. One of those things is the extension version, set using a custom variable every time the background page is started. Now my question is: Which scope should I use, visitor or session level? I can't figure it out based on Google's documentation, and no one else seems to have had this issue. I'm not even sure there's any difference, or maybe it's just something like "it's bad practice to overwrite visitor level variables".
Chrome extensions are have some very specific characteristics and the answer to this question is not applicable to anything that is not a Chrome extension.
From your question I believe you do some basic tracking on your background page, but I assume you also do so on a popup or you fire an event if the user do some action with your extension.
In that case I'll strongly suggest that you use a Visitor Level Custom var.
The problem is that the background page is loaded only once, when the browser opens up, and it's like a tab that stays open and silent, possibly hosting some callback functions for events that may or may not happen.
Because of that once the visitor first loads your extension you'll see a pageview from you background page setting this custom var.
After that there may be a silent period where your extension doesn't track anything, this period can take hours, until hopefully the user interacts with your extensions and tracks additional data to analytics. When it finally happens chances are that over half an hour has passed since the backgroun page loaded. If that is true the visit (or session) that was started by the background page is already over. A visit with no activity for 30 min is closed by analytics. In that case that interaction will spawn a new visit.
If you set the Custom Var as a visit leve variable chances are that when you see interactions on the extension, these interactions won't have the custom var.
This approach has the bad side effect that if the version of your extension changes and the user doesn't reload the browser the version is not going to be updated, and it will be erroneously registered as te old version.
That's very unlikely. And the only way to fix it is to check the version of your app everytime the user does an interaction and set that custom var again. I believe that this is excessive and I don't do it in my extension. Still if you opt for it, it really doesn't matter if it's a visit level or visitor level custom var.

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