You can try PowerShell:
https://superuser.com/questions/1178736/have-a-batch-file-minimize-all-windows-but-itself-or-activate-something-that-can

You can minimize the prompt with these:
https://dnrce.com/articles/run-a-batch-script-minimized
or "start /min":
https://stackoverflow.com/questions/9232308/how-do-i-minimize-the-command-prompt-from-my-bat-file

While I use

taskkill /IM mpc-hc.exe
cscript.exe C:\viewtube_mpc\script.js //Nologo
set video=%1
set video=%video:viewtube:=%
"C:\Program Files\MPC-HC\mpc-hc.exe" %video% /fullscreen

and script.js
(new ActiveXObject('Shell.Application')).MinimizeAll();


I would like to open all the windows after closing the player
for example

script2.js
(new ActiveXObject('Shell.Application')).UndoMinimizeAll();

and 2.bat
waiting for it to close 1.bat
cscript.exe C:\viewtube_mpc\script2.js //Nologo


Is it possible?

If the batch scripts are synchronous, then it should work. Add the second cscript.exe command after the video player command.

Yes! It works. Thank you :)

taskkill /IM mpc-hc.exe
cscript.exe C:\viewtube_mpc\script.js //Nologo
set video=%1
set video=%video:viewtube:=%
"C:\Program Files\MPC-HC\mpc-hc.exe" %video% /fullscreen /close
cscript.exe C:\viewtube_mpc\script2.js //Nologo

Hurried.
If you do not close the player and click the viewtube: link again, the script fires with an error

somehow
...
"C:\Program Files\MPC-HC\mpc-hc.exe" %video% /fullscreen /close
if errorlevel 0 goto M1
:M1
cscript.exe C:\viewtube_mpc\script2.js //Nologo
goto exit

but does not work

You mean he video player doesn't close after playback? Add "/play" to command line or check the settings for "after playback" option.

You can test this by adding these in a batch file and run it in cmdprompt or powershell:

cscript.exe C:\viewtube_mpc\script.js //Nologo
"C:\Program Files\MPC-HC\mpc-hc.exe" "SOMEVIDEO" /fullscreen /play /close
cscript.exe C:\viewtube_mpc\script2.js //Nologo

The bat file does not partially work if you click another viewtube link when the player is open

Doesn't this line kill the player?
taskkill /IM mpc-hc.exe

Kill.

But for some reason, the script.js or script2.js remains in limbo.
I did it, but it doesn't work.
taskkill /IM script.js
taskkill /IM script2.js
For the bat file to work again, you must close it or the player before restarting.

Kill cscript.exe.

What type of playback do you want to use, HTML5 Video, NPAPI (plugin) or external player?

Theoretically, you can force Linux to play the VLC plugin in Firefox 84.0.2 32bit. If you change the VLC plug-in deb version 2.0.6.
deb package 2.0.6 can be unpacked and some edits made to text files (roughly the same as I did for Windows), but I don't know how to collect back the deb package.

I would like to use the external video player VLC. But I want to know how to use a plugin as well. Thanks.

If you can use a browser that still has NPAPI support install browser-plugin-vlc or npapi-vlc. For external player create the files as described on the script's web page.

Thanks again. Later I saw that Chromium dropped NPAPI support since 2015 (sorry for the inconvenience). Thanks @grey_rat for the option of using Firefox 85. By the way, in windows, is it possible to make the NPAPI WMP plugin to work on WEBM video formats? I tried installing K-Lite Codec Pack (Basic) and that let me see WEBM videos on WMP directly but when using the NPAPI plugin of WMP it does not load the video. Cheers.

WMP plugin and K-Lite Codec Pack in Windows Vista+ use Windows Media Foundation https://en.m.wikipedia.org/wiki/Media_Foundation
WMP plugin + K-Lite playback = CPU usage is to browser playback
in K-lite, turning off WMF globally for all programms
WMP plugin does not make sense to use in Vista +

VLC plugin works with Firefox 84.0.2. In 85 does not work

WEBM video without sound. In K-Lite you need to do
https://habrastorage.org/webt/l_/x1/sd/l_x1sdxd7y3pi9ope9byqclmavc.jpeg
https://habrastorage.org/getpro/habr/post_images/72d/3de/16f/72d3de16ff5fe4e34f83dc0cb228dcad.jpg

and Windows
include TLS 1.0
update roots certificates

Yes, I did not type the correct version of Firefox. Thanks for the info!

I have the same issue, but only with external players, with the "Video" option is fine.

Try this update:
http://sebaro.pro/viewtube/files/viewtubetest.user.js

Thank you very much. Now videos in the full version of the site are not interrupted and start instantly. Can you do the same for the mobile version?

Added for mobile.