I developed a web app to display a slideshow, and want to display it on my secondary monitor (Connected via HDMI) with IE's Kiosk mode on Windows 10. Because of CPU and other resources on the shared server, I want to pause the slideshow when the monitor is powered off. (And therefore nobody is seeing it)
Is there a way to detect connected displays from Internet Explorer? Since this is a one-pc kiosk setup, add-ons, etc. are accepted. Triggering javascript/jquery events would be ideal. Thank you!
No, there is no reliable way to detect if a second monitor is physically switched off but still connected via the cable.
I have to ask though: why do you need to physically switch the second monitor off?
As an alternative could you not:
Have the slideshow stop after a timed duration unless it receives an input?
Have the slideshow only on display at certain times of the day?
Accept events from, say, a node server to control when to and not show the slideshow?
Having said that these threads could provided you, albeit unreliably apparently, what you need:
Is there any way to detect the monitor state in Windows (on or off)?
Monitoring a displays state in python?
You can't do in javascript. Why not try some asp component.
http://msdn.microsoft.com/en-us/library/windows/desktop/dd162617%28v=vs.85%29.aspx
You could potentially write a command line program that sits on a particular port, continuously checks for that locally and then use HTML5 WebSockets in IE to communicate with it?
i.e. C# PowerModeChangedEvent
SystemEvents.PowerModeChanged += new PowerModeChangedEventHandler(
SystemEvents_PowerModeChanged
);
I don't think so....
CPU cycles are paused when the client computer is put into Sleep mode. (win+L)
Start>Control Panel>Power
configures how the monitor(s) behave when the client is powered down or put to sleep mode.
the screen object in js returns the metic values (height/width) of the screen object but not its powered state.
the impact of wasted CPU cycles on a powered down secondary monitor should be un-noticable....
probably you have not selected the option to "Use software rendering instead of GPU rendering" on the Advance tab of internet options....
You will notice that your CPU on your desktop will throttle up and the cooling fan will race if you haven't set the above setting when running graphic intensive web pages or canvas scripts.
Related
I was wondering if it is possible to throttle user internet speed when accessing the website, based on a user choice. This is needed for a small scale test of how users react to different internet speeds. My workaround would be to get the user to manually throttle the speed in chrome dev tools, but I would prefer that as the last option. Any option to achieve this or something similar would be amazing. Thank you.
Edit: Just to clarify I am looking to code the throttling functionality within the website itself so the user won't have to install something or set the Chrome dev tools manually, as I am aware of those solutions already.
What you desire to do is not easily possible due to security reasons. Chrome (and most other browsers) prevent DevTools access from js scripts. A user has to manually and interactively press the buttons on DevTools to change the network speed of the chrome tab.
On your behalf, you should get the UX testers to use the DevTools.
That being said, there are solutions for this. But they might be complex!
Solutions in JS:
Dirty fix:
Create looping data downloader script that performs a DOS attack on the client.
Basically something like:
let delay = 100*(Math.random() +0.5);
setInterval(/*downloadStuff*/, delay);
Issues with this fix:
This creates real network congestion on the client, which might not be optimal.
Introduces web page lag because of CPU usage.
Better, but time consuming fix:
You can simulate a slow network environment by doing the following:
Periodically do request.abort() some ajax and xhr requests. See here and here. And yes, you have to keep references to the remote calls. (Some inspirational code by bruth)
Randomly prevent some images from loading by changing their src attribute for a few second. See here.
And... there are more to it.
Iframes are tricky as they can be from another domain. Chrome does not support cross domain request. To simulate a slow network, you have to stop the iframe once in a while and refresh it using the src attribute, just like the images. You could use window.frames[].stop(), to simulate a frozen/stopped iframe.
Videos are sometimes loaded with iframes, which is again hard to simulate network lag on. Unlike, images, reloading a video will reset the playback time. AFAIK, there are no way to simulate video lag easily (without heavy change of video playback logic).
And... if you are really into it. Go ahead and override different events such as those from GlobalEventHandlers.
Many solutions aside from js
Use Chrome DevTools (easiest as mentioned)
If the site is connected to a server you own. Add delay on before responding to simulate server congestion.
Use/create a Chrome Extension that changes the network speed
Create your own browser that can run the site, and change the network speed accordingly
Install software to control networks settings on the OS
Change the network speed on the router
Not entirely sure what experience you want other than the Chrome dev tools way but here is an alternative.
clumsy makes your network condition on Windows significantly worse, but in a managed and interactive manner
https://jagt.github.io/clumsy/
https://serverfault.com/a/570702
I am looking to obtain the bluetooth strength (RSSI or similar) of a signal using a web-based application (in this case attempting with the Web-Bluetooth API). From what I've seen this feature is not supported in a browser (yet at least).
The result was intended to be used on a mobile device rather than a desktop but if there is a solution for either I am unaware at the current minute. Since I cannot see much on the matter of it other than it working within downloaded/compiled mobile apps (which I guess I will have to resort to if this is completely unachievable).
This would also apply to if HTML5 p2p connection strength if that was an obtainable value as well.
Maybe I have completely missed something out and my googling skills are terrible, otherwise any relevant links / information is appreciated :)
I recently implemented the watchAdvertisements() API that will enable the page to listen for advertisement packets from the device. When a packet is received, an advertisementreceived Event is fired on the device, and the Event contains the RSSI and TX Power of the device. You can give this API a try by enabling chrome://flags/#enable-experimental-web-platform-features in Chrome 85.0.4165 or higher.
I know this is not a specific question, but I just want to get design ideas about a screen sharing web site with SignalR.
We want to add a link on our website which is called "Share My Screen" and then our support team be able to see the content of the browser (not whole desktop) and even they be able to click or type on customer browser.
I was thinking to do it as
Taking screen shot from browser by js (by http://html2canvas.hertzen.com for example)
send taken screen shot to server constantly (I don't know how yet)
Server sends the received screen shot to our support team browser
Capturing mouse move and key press on support team browser
Sending this captured data to customer browser
Since each part of this needs a lot of work I just want to gather all possible ideas to find a tested solution
First of all, I do not think your idea of capturing screen is really doable with javascript technology. Security would be a huge issue, you would need to process a high amount of data, and syncing events would be a nightmare no matter how you approach it. Capturing and sharing tab content and events is a much more manageable goal.
If you are aiming to use this for people who can not manage to install a remote control app, then we can count newer technologies such as WebRTC out due to browser compatibility issues.
There is a good blog post discussing this issue here - (Screensharing a browser tab in HTML5?).
I especially like the first method, using Mutation Observer (browser support) and Web Sockets (browser support). It basically syncs two html documents through the use of mutation observer and uses web sockets for communication. You could use SignalR instead of standard web socket API for communication if you prefer.
I have created an iPhone application using phoneGap and i have implemented the Websync functionality using javascript, all functionality are working fine,
but my problem is that When Iphone goes to sleep mode than the app is still open and when you wakeup the phone websync doesnt work anymore.
Generally speaking iOS apps are not allowed to maintain a permanent connections in the background.
http://developer.apple.com/library/ios/#documentation/iphone/conceptual/iphoneosprogrammingguide/ManagingYourApplicationsFlow/ManagingYourApplicationsFlow.html
Keep in mind the following about inactive apps:
Inactive
The app is running in the foreground but is currently not receiving events. (It may be executing other code though.) An app usually stays in this state only briefly as it transitions to a different state.
iOS (and other mobile devices) don't allow JavaScript to run in the background when the device is sleeping. Battery life would suffer tremendously if it did.
However, WebSync 4 should automatically re-connect to the server after waking up. If you are using WebSync 3, you have to set a flag (stayConnected) to get the same behaviour:
client.connect({ stayConnected: true }); // WebSync 3 only
I have an application on Samsung Smart TV. I'm fetching data from web service and display this data in my application.
I'm fetching the data periodically and updating the application accordingly.
I want to run this operation as a background process, so it'll download the data and if there is an update, I warn the user when s/he watching TV.
The other thing I want is to start application on TV launch, is it possible?
Only 'ticker' type application can run in background. It is not supported in Europe and will not pass certification for Samsung Apps store.
Samsung Smart TV suppots push-notifications (samsungdforum.com/Guide/art00080/index.html).
It will allow you to show popup-message on screen with ability to launch your application.
You cannot auto-start application on TV launch.
The only way is to use custom firmware like SamyGo (http://www.samygo.tv/)
About the "background process"... as far as we assume that JavaScript's setTimeout or setInterval can be used to execute application's "internal" background process, there is no problem - Just DO it! :)
But if you were thinking about system's background process - for ex. crontab of device - it's impossible.
for your second doubt
Auto launch of the application is supported in ticker applications only and there is property in config file of the ticker widget :
"<ticker itemtype="boolean">y</ticker>"
if u mark it as y(as above) than you can set up auto launch of the app from
Menu->smart Hub->Apps settings->auto ticker. in 2014 Samsung Smart TV models.
Since Tv has limited memory I wont recommend background process like setInterval or setTimout. You may have refresh button for the same.
And They must have some js api for controlling internal method of tv application (not sure). Anyway if you really want to use interval/timeout dont forget to clear it.
As it shown here, WebSocket is supported by Samsung Smart TV. Your server application can trigger TV application when an update is appear. It is more efficient way than polling server with ajax for your case.
(Edit) I wrote a sample application to demonstrate:
https://github.com/aksakalli/socket.io-hello-world
(Edit 2) I see that your problem is about platform limits. My answer is just about approaches that can be applied then I have very limited experience on Samsung Smart TV.