Function updateButtons

test/runTest/runtime/main.js:218–222

(buttons)

        box.classList.remove('button-' + event.which);
    }, true);
    function updateButtons(buttons) {
        for (let i = 0; i < 5; i++) {
            box.classList.toggle('button-' + i, buttons & (1 << i));
        }
    }
});