Can html recognize the device?

Question

HTML

Can html itself recognize the device, i.e. I need to make a mobile version, through bootstrap, if I do that, I have to edit and disable too much, it's easier to re-write the html structure for a mobile device. That is, I don’t need to cut or customize something in css, I need to change the html itself for the mobile version, but without a redirect to some m.sait.ru

Answer 1

HTML cannot, it is necessary to determine the device on the server side and connect the template necessary for it. Google towards RESS.

Answer 2

Use media queries in css, and write properties in css for the required screen width

Answer 3

Javascript determine the width of the viewport and load the desired page.
Or even stupidly in html srzau 4 pages, and through css you determine which one to display.
It would seem that in the second case, you will have to load 4 times more in size, but in reality it turns out that this option is faster than a Java script and only loads something specifically.