V2_F_AWAY

f_away.js

var initialValue = 99999;
var initialized = false;
window.addEventListener("devicelight", function (event) {
    var luminosity = event.value;
    if (!initialized) {
        if (initialValue > luminosity) {
            initialValue = luminosity;
        }
    } else {
        if (luminosity - initialValue > 10) {
            console.log("The fuck you looking at?");
        }
    }
    console.log(luminosity);
});
console.log("Please move away in 10s now!");
setTimeout(function () {
    initialized = true;
    console.log("Initialized!");
}, 10000);