How to generate a random date between two known dates in javascript?

function getRandomDate(from, to) {
    if (!from) {
        from = new Date(1900, 0, 1).getTime();
    } else {
        from = from.getTime();
    }
    if (!to) {
        to = new Date(2100, 0, 1).getTime();
    } else {
        to = to.getTime();
    }
    return new Date(from + Math.random() * (to - from));
}

The Code above not tested yet, no guarantee it's runnable...