Why does the Internet disappear on inactive tabs?

Question

Browsers

The Internet constantly disappears when the tab is inactive for a long time on the Internet, I did not find information specifically on my topic, only similar ones.
Let's say I have 3 tabs open: YouTube, VK and mail. I watch a video on YouTube for about 10 minutes, then I switch to VK and the browser shows no Internet connection, but if I switch back to YouTube, I can watch videos. And it does not depend on the browser (I tried Yandex, Chrome, Opera, Mazila).
You have to constantly restart your browser. Who has experienced this?

Answer 1

On mobile phones, they came up with the idea of ​​​​turning off inactive tabs, saving memory / processor / network.
Then it also penetrated the desktop, where this is not particularly necessary (except for laptops when running on battery power).