sw.html

<script>
if ('serviceWorker' in navigator) {
    navigator.serviceWorker.register('/sw.js', {
        scope: '/'
    });
}
window.addEventListener("load", function() {
    if (navigator.serviceWorker.controller != null) {
        navigator.serviceWorker.controller.postMessage({
            "command": "trimCache"
        });
    }
});
</script>