javascript - Check if browserplatform support screen capturing via `getDisplayMedia` - Stack Overflow

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We can request a media stream to a screen or windows via navigator.mediaDevices.getDisplayMedia(). However, this immediately prompts the user to decide which kind of capturing to use. I need to check if the browser/platform even support screen capturing.

Of course, it is possible to check for 'getDisplayMedia' in navigator.mediaDevices, but this just tells us if the API is supported by the browser. In particular, on FF and Chrome on Android, the API is defined and I can call getDisplayMedia(), but it always immediately returns a NotAllowedError error (which is to be expected: according to caniuse, the mobile browsers do not yet support getDisplayMedia.)

Next, I tried checking navigator.mediaDevices.getSupportedConstraints(). However, my mobile FF returns the exact same object as my desktop FF. In particular, navigator.mediaDevices.getSupportedConstraints().mediaSource is true in both cases. Finally, the data returned by navigator.mediaDevices.enumerateDevices() does not help me either. I only get a device and group ID which I cannot interpret in any way (right?).

Is it possible to detect whether or not screen capture via getDisplayMedia is supported beforehand?

(Note: this Q&A seems fairly similar, but is about getUserMedia and is already quite old)

We can request a media stream to a screen or windows via navigator.mediaDevices.getDisplayMedia(). However, this immediately prompts the user to decide which kind of capturing to use. I need to check if the browser/platform even support screen capturing.

Of course, it is possible to check for 'getDisplayMedia' in navigator.mediaDevices, but this just tells us if the API is supported by the browser. In particular, on FF and Chrome on Android, the API is defined and I can call getDisplayMedia(), but it always immediately returns a NotAllowedError error (which is to be expected: according to caniuse, the mobile browsers do not yet support getDisplayMedia.)

Next, I tried checking navigator.mediaDevices.getSupportedConstraints(). However, my mobile FF returns the exact same object as my desktop FF. In particular, navigator.mediaDevices.getSupportedConstraints().mediaSource is true in both cases. Finally, the data returned by navigator.mediaDevices.enumerateDevices() does not help me either. I only get a device and group ID which I cannot interpret in any way (right?).

Is it possible to detect whether or not screen capture via getDisplayMedia is supported beforehand?

(Note: this Q&A seems fairly similar, but is about getUserMedia and is already quite old)

• javascript
• getusermedia
• mediadevices
• get-display-media

Share Improve this question Follow edited Nov 13, 2019 at 18:04 Lukas Kalbertodt asked Nov 13, 2019 at 17:49 Lukas KalbertodtLukas Kalbertodt 89.3k3232 gold badges274274 silver badges334334 bronze badges 6

• Are you using HTTPS? – str Commented Nov 13, 2019 at 18:00
• @str Yes, I am. Also note that this question is not about "I can't use getDisplayMedia on mobile". That is fine for me. I just want to check whether or not it is supported. – Lukas Kalbertodt Commented Nov 13, 2019 at 18:01
• Doesn't getDisplayMedia return a promise? – aksappy Commented Nov 13, 2019 at 18:30
• @aksappy Yes. Why? I don't see how that would help me. Either it resolves immediately to an error (on mobile) or the user get prompted by the browser (desktop, if supported). – Lukas Kalbertodt Commented Nov 13, 2019 at 18:34
• Well, that was more of a conversation starter :-) Have you looked at MediaRecorder? It solves your use case with a isTypeSupported method. – aksappy Commented Nov 13, 2019 at 19:05

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1 Answer 1

Sorted by: Reset to default 9

Unfortunately, there's no direct way to feature-detect whether getDisplayMedia will work on those browsers.

All you can do today is browser-sniff the UA string to detect you're not on mobile, where support is lacking.¹

I've filed an issue on the spec based on your question, to see if getDisplayMedia is better left undefined when unsupported.

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_{1. caniuse claims Opera Mobile has support, but this appears not so when I test it.}

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