JS get viewport width

//getting the viewport dimensions
var width= Math.max(document.documentElement.clientWidth, window.innerWidth || 0);
var height = Math.max(document.documentElement.clientHeight, window.innerHeight || 0);

// viewport dimention 
const vw = Math.max(document.documentElement.clientWidth || 0, window.innerWidth || 0);
const vh = Math.max(document.documentElement.clientHeight || 0, window.innerHeight || 0);