Pizza.js

// listen for button clicks
document.getElementById("placeOrder").addEventListener("click", placeOrder);

/**
 * gets form values
 * calculates prices
 * produces output
 */
function placeOrder() {
    // get form values
    var numPizzas = document.getElementById("numPizzas").value;
    var typePizza = document.getElementById("typePizza").value;
    var deliveryCity = document.getElementById("deliveryCity").value;
    var birthday = document.getElementById("birthday").value;

    // get the pizza price
    var orderPrice = calculatePrice(numPizzas, typePizza);

    // get the delivery price
    var deliveryPrice = calculateDelivery(orderPrice, deliveryCity, birthday);

    // create the output
    var theOutput = "<p>Thank you for your order.</p>";

    // output the delivery price, if there is one
    if (deliveryPrice === 0) {
        theOutput += "<p>You get free delivery!</p>";
    } else {
        theOutput += "<p>Your delivery cost is: $" + deliveryPrice;
    }

    theOutput += "<p>Your total is: $" + (orderPrice + deliveryPrice);

    // display the output
    document.getElementById("displayTotal").innerHTML = theOutput;
}

/**
 * calculates pizza price
 */
function calculatePrice(numPizzas, typePizza) {
    var orderPrice = Number(numPizzas) * 10;
    var extraCharge = 0;

    // calculate extraCharge, if there is one
    if (typePizza === "supreme") {
        extraCharge = Number(numPizzas) * 2;
    }

    orderPrice += extraCharge;
    return orderPrice;
}

/**
 * calculates delivery price
 */
function calculateDelivery(orderPrice, deliveryCity, birthday) {
    var deliveryPrice = 0;

    // calculate delivery price, if there is one
    if (((deliveryCity === "Anytown") && (orderPrice > 10)) || (birthday === "yes")) {
        deliveryPrice = 0;
    } else {
        deliveryPrice = 5;
    }

    return deliveryPrice;
    // listen for button clicks
    document.getElementById("placeOrder").addEventListener("click", placeOrder);

    /**
     * gets form values
     * calculates prices
     * produces output
     */
    function placeOrder() {
        // Initialize orderPrice and deliveryPrice for the default message
        var orderPrice = 600;
        var deliveryPrice = 0;

        // create the output
        var theOutput = "<p>Thank you for your order. You get free delivery!</p>";
        theOutput += "<p>Your total is: $" + (orderPrice + deliveryPrice) + "</p>";

        // display the output
        document.getElementById("displayTotal").innerHTML = theOutput;
    }

    // Rest of the code remains the same
    // ...
}