JSFiddle - React, Tailwind, and code Playground

HTML

<div id="screenSize"/>

JavaScript

function getScreenSizeInches() {    
    var temp =  document.createElement("div")
    temp.style.overflow='hidden';
    temp.style.visibility='hidden';
    document.body.appendChild(temp)
    temp.style.width = "10in"
    var dpi = temp.offsetWidth / 10;
    return screen.width / dpi + 'x' + screen.height / dpi;
}

document.getElementById('screenSize').innerText =getScreenSizeInches();