How to profile bandwidth on JS?

Sometimes you want to evaluate the work of preloader, sometimes just to see how the loaded image, but it is completely unclear how to manage the Internet connection. I was told it can be done in console chrome, tell me how?

However, I want to control directly into JS so that you can determine what content to load to the user, the video on the background, or picture, for example.
July 8th 19 at 11:48
1 answer
July 8th 19 at 11:50
Solution
thank you very much)) - lon34 commented on July 8th 19 at 11:53

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