cart.js

function validateForm() {
    if (deliveryMethod == "isDelivery") {
        var date = document.forms["cart-form"]["attributes[Delivery Date]"].value;
        if (date == "") {
            $(".o-cart-form__delivery-method-content").addClass("has-error")
            return false;
        } else {
            return true;
        }
    }
    if (deliveryMethod == "isPickup") {
        var date = document.forms["cart-form"]["attributes[Pickup Date]"].value;
        if (date == "") {
            $(".o-cart-form__delivery-method-content").addClass("has-error")
            return false;
        } else {
            return true;
        }
    }
}