var range;

function add(html, id) {
    const old = document.getElementById(id)
    if (old !== null) {
        old.remove()
    }
    if (range === undefined) {
        var range = document.createRange()
        range.setStart(document.body, 0)
    }
    document.body.appendChild(
        range.createContextualFragment(html)
    )
}

function remove(id) {
    const old = document.getElementById(id)
    if (old !== null) {
        old.remove()
    }
}

const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

const letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 
    'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'];

function parseMonth(month) {
    if (month > -1 && month < 26) {
        return months[month]
    } else {
        let first = letters[month%26].toUpperCase()
        let middle = letters[month*13%26]
        let last = letters[month*50%26]
        return first + middle + last
    }
}

function parseDate(date) {
    return parseMonth(date.getUTCMonth()) + ' ' + date.getUTCDate() + ', ' + date.getUTCFullYear() + ' ' + date.toLocaleTimeString();
}