setViewport.js

if(navigator.userAgent.match(/iPad/i)) {
    const ORIGINAL_WIDTH = 1024;
    const ORIGINAL_HEIGHT = 768;
    // screen.height === actual device width
    // screen.width === actual device height
    const w = screen.height;
    const h = screen.width;
    const BROWSER_TABS = h - window.innerHeight;

    const WIDTH_SCALE = Math.round(w / (ORIGINAL_WIDTH / 100)) / 100;
    const HEIGHT_SCALE = Math.round((h - BROWSER_TABS) / (ORIGINAL_HEIGHT / 100)) / 100;

    document.querySelector("body").style.transform = `scale(${WIDTH_SCALE}, ${HEIGHT_SCALE})`;
    document.querySelector("body").style.transformOrigin = `top left`;
}