rt button

// timer update
U=e=>
{
    // update time
    (t = Math.max(0,   // stop at 0
        M.value * 60 + // minutes
        S.value*1 - 1))  // seconds minus 1

    // play alarm sound and show popup
    || (zzfx(...[2,.8,999,,,,1,2,,,,,1,,,.1,.2]),
        --P%10 ||                                  // every 10 seconds
        (parent.document.hasFocus() || !P) &&      // has focus or first popup
        OS13k.Popup('<div style=font-size:40>âŒ›</div><b>' + OS13k.StripHTML(N.value),