js-generate-random-color.txt

function getActivityColor(activityID) {
    var color;
    for (var key in activityColors) {
        if (activityColors[key].activityID == activityID) {
            color = activityColors[key].color;
            break;
        }
    }
    if (!color) {
        var letters = '0123456789ABCDEF'.split('');
        var color   = '#';
        for (var i = 0; i < 6; i++) {
            color += letters[Math.floor(Math.random() * 16)];
        }
        activityColors.push({"activityID": activityID, "color": color});
    }
    return color;
}