give gray offlien scale to website
window.addEventListener('online', function(e) {
// add your logic to update the UI when online
console.log("You are online");
document.body.style.filter = 'grayscale(0)';
}, false);
window.addEventListener('offline', function(e) {
// add your logic to update the UI when offline
console.log("You are offline");
document.body.style.filter = 'grayscale(1)';
}, false);