async function keyDownHandler(e) {
    e.preventDefault();

    var element = Array.from(document.querySelectorAll('div.dialog'))
        .filter(e => e.style.visibility == 'visible')
        .map(e => ({ element: e, zIndex: parseInt(e.style.zIndex) }))
        .sort((a, b) => b.zIndex - a.zIndex)
        .map(e => e.element)[0];

    if(element) {
        await window.dialogObjects
            .find(d => d.element == element)
            .dialogObject
            .invokeMethodAsync('KeyHandler', e.key);
    }
}

window.onload = () => document.onkeydown = keyDownHandler;