Open Source Digital Signage !free! -

if (countdown <= 5) timerElement.style.background = 'rgba(255,0,0,0.8)'; else timerElement.style.background = 'rgba(0,0,0,0.7)';

Use the "Web Page" asset type pointing to your display URL open source digital signage

// Reset countdown countdown = qrData.duration if (countdown &lt;= 5) timerElement

Add the HTML file URL as an asset