I'm developing a website, in which I need to ensure that some pages won't be opened in more than one tab / browser. I need some sort of client identification. As I know MAC address cannot be queried using javascript.
I know that Netflix does something just like this, when opening two tabs of video watching, Netflix prompt an error that I'm already watching. Even if I'm using a different browser, Netflix can still tell I have another browser which is watching a video, which means they don't use cookies for this.
So in short, how can a web app distinguish between computers? How Netflix does that?
Related
How do I detect the number of windows open on the screen?
Like for example, if I have chrome, visual studio, notepad open, I need to get the number of windows open as 3.
Is there a way to detect the number of windows open, specifically from a screen share or via javascript as the application is going to be an online exam taking website?
Websites are highly sandboxed programs. They don't communicate with the OS directly, only through Web APIs. If the feature you want is not available in the Web APIs, you cannot use it.
I don't know every Web API, but i don't think there's any that gives access to the number of open windows. The Screen Capture API looks promising, but I found no method that returns the number of open windows.
Also, even if there was, you would be trusting the user that he/she didn't modify your client (your client-side code), and I believe in this case you don't want to trust the user.
I'm currently developing a web app that allows users to add a list of websites that they want to block i.e. preventing them from accessing the website from their browser.
Ideally I want to be able to block websites on every browser but this is difficult, so I narrowed my research to just Chrome for now. I came across the chrome.webRequest api which seems promising but it specifically says its for chrome extensions and am unsure if it would work for my web app.
Can anyone point me in the right direction for blocking websites on a web app, ideally using javascript. Any help is much appreciated!!
EDIT:
1) I forgot to mention that I'm using firebase for my backend.
2) People have been saying that I can't block websites outside the web apps scope, if I instead used electron to make the web app a desktop application would it then be possible?
Firstly you have a database containing URL of blocked websites. URLs are modified using your web app. That's one part. Now your problem is how to make the browser work with your database.
The only possible way for you to share blocked URLs with the browser is via API. You must have API that can communicate outside your web app.
Now browsers such as chrome/firefox give users the power to make changes inside and outside the dom. For chrome, you have chrome extension where Google provides API so the users can manipulate actions outsides regular actions such as manipulating dom. An example I can give that is closely related to your subject matter, which is an action activated before/after a user enters URL on the search box and for that, we use the following API from https://developer.chrome.com/extensions/webRequest
And it's same for Firefox.
What I want to do
Make a simple socket connection to a server on the browser. I want to not send any header information with the socket connection.
The Problem
It looks like I am unable to make a socket connection with javascript that does not send header data (Is there a way to do a tcp connection to an IP with javascript?).
I thought maybe I could make a connection with a chrome extension, however it looks like the socket API is only available for chrome apps (Google Chrome Socket API in extensions).
I am thinking that I might need to make a native application that will make socket connections through requests made by the browser using Native Messaging.
Is there anyway I can achieve this or am I out of luck?
Raw socket connections through the browser are wrapped up in security concerns. Users can be easily manipulated to allow things to run that shouldn't.
TCP and UDP Socket API
W3C Editor's Draft 20 January 2016
is located here.
http://raw-sockets.sysapps.org/
Mozilla's API information here: https://developer.mozilla.org/en-US/docs/Archive/B2G_OS/API/TCPSocket "This API is available on Firefox OS for privileged or certified applications only."
If you work with raw TCP connections. I would suggest
(1) downloading PHP onto the local computer. PHP has a developer web host build in so you can run whatever application you want on PHP using the browser as your GUI.
(2) download node.js.
You are not out of luck you just need to achieve it with the understanding that you are working outside the box for normal browser based scripting created from security concerns, and that means the user/client needs to install something manually.
If you must use chrome browser on the client side, you will need to make an -extension- correction webapp. You can as a developer make one that you can use on your own computers.
https://developer.chrome.com/extensions/getstarted
https://developer.chrome.com/apps/first_app
Load the extension#
Extensions that you download from the Chrome Web
Store are packaged up as .crx files, which is great for distribution,
but not so great for development. Recognizing this, Chrome gives you a
quick way of loading up your working directory for testing. Let's do
that now.
Visit chrome://extensions in your browser (or open up the Chrome menu
by clicking the icon to the far right of the Omnibox: The menu's icon
is three horizontal bars. and select Extensions under the Tools menu
to get to the same place).
Ensure that the Developer mode checkbox in the top right-hand corner
is checked.
Click Load unpacked extension… to pop up a file-selection dialog.
Navigate to the directory in which your extension files live, and
select it.
Alternatively, you can drag and drop the directory where your
extension files live onto chrome://extensions in your browser to load
it.
If the extension is valid, it'll be loaded up and active right away!
If it's invalid, an error message will be displayed at the top of the
page. Correct the error, and try again.
This insures that non developers don't load an extension which does not comply with the normal security concerns.
Communicating between with the script on the web page to the extension.
Can be done with message passing ... https://developer.chrome.com/extensions/messaging
The extension can add content directly to the web page which is available to the script on the web page. If for example the extension replaced the web cam image with a static image when the webcam script reads what it believes is the webcam it gets the static image instead, which explains why I look like an alien from space on the webcam. Although I did not create an extension to do that, I merely modified an existing extension to replace the function that gets the webcam image with a function to get a static image.
You can use SignalR, it is javascript library (JQuery Plugin) and it enables you to open web sockets from the browser to a server. Please check the following links:
https://blog.3d-logic.com/2015/03/29/signalr-on-the-wire-an-informal-description-of-the-signalr-protocol/
http://blog.teamtreehouse.com/an-introduction-to-websockets
https://github.com/SignalR/SignalR
I am working with a website having a chat functionality (think Facebook chat).
I'd like to play a notification tone when a new message arrives. However, the user may have multiple tabs opened and the message arrives to the multiple tabs, as the chat session is multiplexed across different browser tabs/windows.
How to determine
If a browser has many tabs (windows) open for the same website
When a new message arrives which of the tab(s) should play a sound effect
I am aware of the Notifications API, but I'd like to solve this problem in backwards-compatible manner. Also if there are any related JavaScript libraries I would like to know about them.
You can use localStorage for such purposes. Data in localStorage is shared between all windows (tabs or iframes) with the same origin. It also can notify your application about changes in localStorage.
See IWC library. I think it will help with your tasks.
I have developed a site for use on my company's intranet. You can not access the site from outside of the network.
Asking users to log-in pretty much means they won't use it as logging in is seen as cumbersome. I am trying to find the most seamless way of grabbing some identification.
I used Javascript and Chrome to develop the site. I would like to have a way to grab a computer name or windows user name or something that will uniquely identify the user. A chrome extension would work.
I understand ethical issues with an application on the internet doing this, but this is for internal use only.