How to display div true (by ruler) width strictly 100mm?

Question

Layout

Don't rush to answer.
The bottom line is this: if you just write: it will, of course, be displayed, but I need true 100 mm (that is, if you attach a ruler to the screen, the block width would be exactly 100 mm). Is it possible to somehow determine the dpi of the user's screen and calculate the number of pixels in true 100mm? <div style="width:100mm"></div>

Answer 1

Google it, maybe something like that will help.
https://stackoverflow.com/questions/17969/how-to-access-screen-dis...
You're less likely to be helped by using media queries with pixel density and resolution.. something like that.
@media
only screen and (-webkit-min-device-pixel-ratio: 2) and (min-width: 700px),
only screen and ( min--moz-device-pixel-ratio: 2) and (min-width : 700px),
only screen and ( -o-min-device-pixel-ratio: 2/1) and (min-width: 700px),
only screen and ( min-device-pixel-ratio: 2) and (min- width: 700px),
only screen and ( min-resolution: 192dpi) and (min-width: 700px),
only screen and ( min-resolution: 2dppx) and (min-width: 700px) {