var current_page = 1;
var records_per_page = 10;
var l = document.getElementById("listingTable").rows.length

function prevPage() {

    if (current_page > 1) {
        current_page--;
        changePage(current_page);
    }
}

function nextPage() {
    if (current_page < numPages()) {
        current_page++;
        changePage(current_page);
    }
}

function changePage(page) {
    var listing_table = document.getElementById("listingTable");
    var page_span = document.getElementById("page");

    // Validate page
    if (page < 1) page = 1;
    if (page > numPages()) page = numPages();

    [...listing_table.getElementsByTagName('tr')].forEach((tr) => {
        tr.style.display = 'none'; // reset all to not display
    });
    listing_table.rows[0].style.display = ""; // display the title row

    for (var i = (page - 1) * records_per_page + 1; i < (page * records_per_page) + 1; i++) {
        if (listing_table.rows[i]) {
            listing_table.rows[i].style.display = ""
        } else {
            continue;
        }
    }

    page_span.innerHTML = page + "/" + numPages();
}

function numPages() {
    return Math.ceil((l - 1) / records_per_page);
}

window.onload = function () {
    changePage(current_page);
};