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Detect and deflect Javascript injected from Inspector

Short version:
Is it possible to detect that someone added code to run inside a page from the browser inspector?
Long version:
Stock broker companies give their users the real time value of stocks, other free tools give you a delayed version of such values, for example 15 minutes old information.
There are other types of financial companies that have real time API to give you access to stock market at a cost.
What some people do is to keep their browsers open in the broker site and inject some JS code to observe the changes and post them elsewhere using XHR or web sockets. Not only network calls but also notification API and the draft Serial API can be exploited to put data out of the site.
This usually can't be done automatically due to the secure nature of logins requiring captcha or other methods. But once logged in and injected the hack will work until the tab is closed.
Usually this is not done by injecting script tags with outer files source, just pasting the whole code inside inspector and running it.
Now back to the question: Can a site know that code rogue code is running in their site?
I thought of some methods like a HASH of every variable used and if anything new is created it reloads the page or warn the user. But I'm not sure it is possible in nowadays JS, I guess document.all could help.

So yes, kinda, and also no kinda... there isn't a great cross browser solution to this as their implementation of the debug tools are all slightly different. This solution is probably the best I've found so far.

Find current version AND Adobe's latest version of Flash

Recently, we found that Firefox had made a change towards plugins, such that the user will be temporarily blocked from running them if they are not using the latest version. Our site requires Flash to play sound and interact with the user's webcam/microphone, so we need to do whatever we can to ensure they're not getting these warnings.
One way suggested to me is to create a small Flash control, and wait for it to tell Javascript that it's been initialized. If not (and the user is using Firefox) then they are taken to a page prompting them to update. This may work, but I worry about its reliability, and about running it on every page in our site.
Alternatively, I've been researching a way to use Javascript to detect versions, without making a Flash control. I not only need the user's current version of Flash, but also the version Firefox will expect - and I haven't found an autonomous way of doing so. I don't want an admin to have to change a small value each time Adobe releases a new version. Does anyone have any advice how I could find Flash's latest available version, or an alternate way to solve my problem?

I recommend you have a look at SWFOject and the Express Install option which should ease upgrading considerably.

I just noticed someone upvoting this question, so I thought that I would provide my eventual solution, which I think reduced the impact of a recent issue where Firefox blocked the most recent edition of Flash, pending Adobe's fix.
Basically, I went with a variation on the second paragraph in my question. It does not direct the user to a new page; instead, it opens a dialog over the current page that explains it's having issues communicating with Flash. (It does not specifically say "Your Flash is out of date" because this can also happen if the browser is hiding flash under a Yes/No user dialog). It also contains a small fake flash object, with the idea being that if the browser wants to display a security warning, accept prompt, etc., it can do it inside that space.
The dialog goes away on its own if said Flash control ends up making its callback to JavaScript. It also installs a variable under sessionStorage so we don't bother checking for it again (Flash takes enough time on some computers that you might see the dialog for a split second).

Is there a way to determine if a Javascript client is using a phone on a mobile network as opposed to wifi?

I'm trying to make a site as responsive as possible for phone users, and that means removing several bandwidth-hungry features. In particular, I'd like to load an external font if the user is on wifi but not on 3g/4g.
A pretty good proxy for this is 'phone or tablet', with tablets usually being the cutoff for 'good connection'. This kinda works, but there are 3g/4g tablets, and there are phones on wifi, so it's not perfect.
I don't think it's possible to get this any better, but perhaps stackoverflow's collective wisdom has discovered a way. Is this detectable?

Rather than focusing on mobile or not, just do a bandwidth test. The only way to really be sure is measure the time to download a file to their device.
Try the accepted answer here: How to detect internet speed in Javascript?

You can try the solution suggested in this answer, that is to use navigator.connection.type. However, this is definitely non-standard and it seems to be limited to Android devices only. Also, see the MDN entry, which mentions a metered property on the same navigator.connection object - this may also be useful.
For the best coverage: var connection = navigator.connection || navigator.mozConnection || navigator.webkitConnection;

The only way to do this I know of, which has it's own problem, is to do a reverse lookup on the IP address of the request at the time of the request (on the web server) and see if it's from a Wireless Carrier. The two problems with this are; that I don't know if mobile devices use a different network than say wired networks (Version Wireless vs Version Fios), and the other problem is employees of those companies who may actually be wired will appear wireless.

You could try doing a network probe for very common local addresses (only reachable over Wifi), such as 192.168.1.100 and friends. Here's how:
Create an img element with an onError handler.
Set the src property to the address you want to "ping"
If you get an error, then you know the address does not exist
No error means the address exists
I initially read about this technique in Ajax Security (great book).

JavaScript does not provide any hooks into network-level connection types. The best you can do is time the download of a known test file and decide based on that.
If that fails, just ask the user if they prefer the high/low bandwidth setting.

how to start up a desktop application in client side

In my web page, I have to start a desktop application on the client's computer if it's installed. Any idea how I can do this?
If the application is MS Office or Adobe Reader, I know how to start them, but the application I want to start is a custom application. You can not find it on the internet.
How can I open the application?

Basically it's not possible to achieve unless an application registers a protocol that will trigger it. If it does that all you need to do is to provide a link using this protocol
yourcustomapp://some.parameters
Another way the 3rd party app can integrate with the browser is if it hooks to it as a plugin. This is how flash apps work etc.
If the app you are trying to launch does not support something like that it's going to be close to impossible to achieve what you want.

The browser sandbox prohibits you from executing local resources, for good reason - to thwart a website destroying your box with malicious code. I've been researching the same functionality.
The only solution I've found is to build an extension in Mozilla Firefox which can launch your app. Extensions live outside the sandbox so they can execute local resources. See this page for how to do that. You may be able to do it cross-browser using crossrider, though I haven't had success with that yet.
You could alternatively build a thick client populated from a web service, and launched from the browser through an extension as mentioned above. This is what I'm doing to get around the sandbox. I'm using local XUL for this.
See my question for additional discussion.

First off - you can't do it using javascript in any sort of a portable mechanism.
If the application is ms office or adobe reader,I know how to startup them
No you don't - you know how to send a document, which the browser associates with these applications and invokes them supplying the name of the local copy of the response. You can't just start the programs.
You just need to do the same for your app - invent a new mime type (the major type would be 'application' and by convention, non-standard minor types are prefixed with 'x-', so you might use application/x-hguser) then associate that mimetype with the relevant program browser side.
i.e: You need to explicitly configure each browser

I already encouter that problem in some complex production environnements.
I do the trick using the following code :
function launch(p_app_path)
{
var oShell = new ActiveXObject("WScript.Shell");
oShell.Run('"' + p_app_path + '"', 1);
}
In IE options > Security > Customize the level > ActiveX controls and plugins > Initialization and script ActiveX controls not marked as safe for scripting, set the value to Ask or Active.
It isn't a security problem when your website is enclosed into a specific security context.
And as they say, it's not worth it to build a gas plant.

JavaScript alone can't do this. (No, not even with MS Office or Adobe Reader.) Thankfully.
There are a number of old ways, including using ActiveX, which may work for your needs. As others have pointed out while typing this, you can customize responses based on the mime type or the protocol, etc.
Any way you look at it, you're going to need control over the end users' browser. If you're in a close environment where you can dictate policy (users must use a specific browser, with a specific configuration), then you're going to need to do that. For an open environment with no control over the end users, you're out of luck.

I'm actually having a lot of success right now with SiteFusion. It's a PHP client/server application framework that serves out XUL/JavaScript applications from a server deamon running in Apache. You access applications from a very thin client in XULRunner, or potentially off a web page using extensions. Clients can execute on any platform, and they're outside of the browser sandbox so you can access local resources such as executables. It'a a fairly elegant solution, their website provides great examples and documentation, and their forum is very responsive. I actually found a minor bug in passing arguments to local executables, posted a question about the forum, and it was fixed by the chief developer in under 15 minutes. Very impressive, overall!

How are windows executables [.exe] launched out of browsers?

I'm not talking about browser exploits. I'm talking about real applications used in real companies, like Ijji and Nexon.
Basically, from their websites you can click a "Start Game" button, which will launch an executable located at c:\ijji\english or c\nexon[gamename] respectively. These applications are real desktop applications, meaning that they can take advantage of the filesystem, direct3d, and OS [in the form of executing other applications]. The applications can also be launched through command line [as opposed to going to the game host's website].
I figured this would be possible if the application created an ActiveX object to call for the creation of a new process. However, the websites are able to launch applications from multiple browsers other than Internet Explorer, including chrome, which, to my knowledge, does not implement ActiveX.
Obviously the people developing these applications use their own means to do this.
From looking at the services list as well as currently running applications list, I have no indication that they're running something like "gameLaunchingServer.exe" which listens to some obscure port for an incoming connection [to be accessed using iframe - HTTP Protocol] and responds by launching an application...
I'm stumped, and this is sort of stuck in my mind. Obviously, they're not using some random browser exploit, otherwise people at http://www.[insertMaliciousWebsiteHere].com would have jumped on the opportunity already to install random crap. Regardless, it seems pretty cool, and I wanted to know how it worked.
Just curious, hehe.

I believe what they're doing is setting up their own protocol handler on install - when a browser is asked to access an address with a protocol that it doesn't know how to handle (for instance, a steam:// address), it looks at all the installed protocol handlers to find a match.
So you can register your application as a myApplication:// protocol handler, and then your web page can link to a myApplication:// address and launch your application.

I didn't quite find the button you are talking about, but I'm thinking it works only after you installed the application once, isn't it?
In that case, the application probably created its own protocol, just as skype, msn and a bunch of clients.

Having a protocol is the easiest way (and very easy indeed to implement - a simple registry key).
Another way which is used is an extension or plugin.

I thought they were run through plug-ins or like applets.
For example, MS SilverLight