time-ticker is a non-visible custom element that fires an event periodically.

Uses this library, explained here.

<time-ticker loop repeat="10" duration="200"></time-ticker>

Demo

time-ticker uses JSON modules, which seem to be wending their way, ever so slowly, into Firefox and Safari.

In the meantime, use the polyfill to accommodate non chromium browsers:

    <script type="esms-options">{ "polyfillEnable": ["json-modules"] }</script>
    <script async src="https://ga.jspm.io/npm:es-module-shims@1.4.6/dist/es-module-shims.js"></script>