function updateUrl() {
    console.log("inside updateUrl function");

    const baseUrl = "/CustomOrderItemAdd?storeId=385303&langId=-1&calculationUsageId=1&URL=AjaxOrderItemDisplayView&calculateOrder=1&authenticate=0&orderId=.&isDirectLink=true&promoCode=";
    let selectedEntries = [];
    let quantityEntries = [];
    let catEntryIndex = 2;

    // Get the first checkbox and check if it's selected
	const firstCheckbox = document.querySelector('.custom-checkbox');
    if (firstCheckbox.checked) {
        selectedEntries.push(`catEntryId_1=${firstCheckbox.value}`);
        quantityEntries.push(`quantity_1=1`);
    }

    // Loop through other checked checkboxes
    document.querySelectorAll('.upsellOptions input[type="checkbox"]:checked').forEach(function(checkbox) {
        if (checkbox !== firstCheckbox) {
            selectedEntries.push(`catEntryId_${catEntryIndex}=${checkbox.value}`);
            quantityEntries.push(`quantity_${catEntryIndex}=1`);
            catEntryIndex++;
        }
    });

    // Build the final URL
    var finalUrl = baseUrl + (selectedEntries.length ? '&' + selectedEntries.join('&') + '&' + quantityEntries.join('&') : '');
    
    // Update the href attribute of the link
    var linkElement = document.getElementById('certificationLinkBuy');
    var linkElement2 = document.getElementById('certificationLinkBuyPop');
    if (linkElement) {
        linkElement.href = finalUrl;
        linkElement2.href = finalUrl;
        console.log("Updated href:", linkElement.href); // Log the updated href
    } else {
        console.log("Element with id 'certificationLink' not found");
    }
}