How to change DPI/pixel ratio/zoom/size/scale of a page via JS or CSS?

Question

css

I want to make a slider to change the DPI of the site in the same way as Ctrl +and Ctrl -, since mobile browsers do not have zoom. It would also be interesting to change the DPI with a pinch gesture. Didn't google anything good :(

Answer 1

Well, the only thing that comes to mind is to change the meta viewport tag with a script.
But I'm very unsure if this will work - it seems that this tag is only processed once on page load.
Most likely, this is not possible at all.

Answer 2

transform: scale(sx[, sy]);
But where did you get the idea that there is no zoom in mobile browsers?
Everything is fine with two fingers and a double-tap is zoomed.