Javascript提示框在表单回发时显示两次

当选择选项被更改时，我使用javascript函数提交一个包含选择框的表单。然后，如果选择的值设置为某个值（在本例中为“new cart”，因为这是针对电子商务网站），则会触发javascript提示框。javascript在选项更改时成功提交表单，当选择特定值时，它确实会显示提示框，但是，它会显示提示框两次，我不知道为什么

这是我的选择框的代码。它位于类函数中。它工作正常

public function printCartsList($id = null, $mini = "true"){ 

    print '<form method="POST" name="cartSelectForm" action="home.php">';

        print '<select name="cartList" id="' . $id . '" data-mini="' . $mini . '" onchange="submitCartForm()" data-icon="false">';

            print '<option value="newuniquecartid1234567890">*** New Cart ***</option>';

            for($i = 0; $i < sizeof($this->savedCarts); $i++){
                if(isset($_SESSION['activeCart']) && $_SESSION['activeCart'] != "new cart"){
                    $cart = new Cart();
                    $cart = unserialize($_SESSION['activeCart']);
                    if($cart->GetCartName() == $this->savedCarts[$i]->GetCartName()){
                        print '<option value="' . $this->savedCarts[$i]->GetCartName() . '" selected>' . $this->savedCarts[$i]->GetCartName() . '</option>';
                    }
                    else{
                        print '<option value="' . $this->savedCarts[$i]->GetCartName() . '">' . $this->savedCarts[$i]->GetCartName() . '</option>';
                    }
                }
                else{
                    print '<option value="' . $this->savedCarts[$i]->GetCartName() . '">' . $this->savedCarts[$i]->GetCartName() . '</option>';
                }
            }

        print '</select>';

    print '</form>';

}

此if语句捕获它（不必要的代码已被删除）：

这将调用newCart函数（删除不必要的代码，上面的完整函数）

上面的DisplayInputBox javascript函数设置了一个cookie，在这里被选中（代码已被删除）（基本上这里唯一相关的事情是我取消了之前设置的cookie。可能不太重要

if(isset($_COOKIE['newCartName'])){

    $success = $customer->UpdateCart($cart);

    if($success == false){
        $customer->AddCart($cart);
    }

    setcookie('newCartName',"",time()-3600);

}

---

希望这更清楚。如果我还需要进一步完善，请告诉我。

很抱歉，这对我们来说太多了。请编辑这篇文章，并将代码限制在生成javascript提示的范围内。好的。我已经编辑了我的文章。我将原始内容留在那里，以备参考，以防删除太多，但出于安全考虑mlined版本，只需查看编辑下方的所有内容。此评论对讨论没有帮助@Ohgodwhy，当我看到这个相当大的问题时，您的用户名就是我所说的。

function newCart(){
    $cart = new Cart();
    $customer = new Customer();

/************could this be the problem?*************/
    echo "<script>DisplayInputBox();</script>";

    if(isset($_SESSION['customer'])){
        $customer = unserialize($_SESSION['customer']);
    }

    $cart->SetCartName("newCart");

    $customer->AddCart($cart);

    $_SESSION['customer'] = serialize($customer);
    $_SESSION['activeCart'] = serialize($cart);

    //echo '<meta http-equiv="refresh" content="0">';
}

function addToCart($item){

    $cart = new Cart();
    $customer = new Customer();
    $newCart = false;

    if(!isset($_SESSION['activeCart'])){
        $_SESSION['activeCart'] = "new cart";
        newCart();
        $newCart = true;
    }
    elseif($_SESSION['activeCart'] != "new cart"){
        $cart = unserialize($_SESSION['activeCart']);
    }
    else{
        newCart();
        $newCart = true;
    }

    $cart->AddToItems($item);

    if(isset($_SESSION['customer'])){
        $customer = unserialize($_SESSION['customer']);
    }

    if($_SESSION['activeCart'] != "new cart"){
        $customer->UpdateCart($cart);
    }
    else{
        $customer->AddCart($cart);
    }

    if($customer->GetLoggedInStatus() > 0){
        //$customer->SaveCarts();
    }

    $_SESSION['activeCart'] = serialize($cart);
    $_SESSION['customer'] = serialize($customer);

    if($newCart == true){
        echo '<meta http-equiv="refresh" content="0">';
    }

}

                       <?php

                            if(isset($_COOKIE['newCartName'])){
                                $customer = new Customer();
                                $cart = new Cart();
                                if(isset($_SESSION['customer'])){
                                    $customer = unserialize($_SESSION['customer']);
                                }
                                else{
                                    $customer->SetLoggedInStatus = 0;
                                }
                                if(isset($_SESSION['activeCart'])){
                                    if($_SESSION['activeCart'] != "new cart"){
                                        $cart = unserialize($_SESSION['activeCart']);
                                        $cart->SetCartName($_COOKIE['newCartName']);
                                    }
                                }

                                $success = $customer->UpdateCart($cart);

                                if($success == false){
                                    $customer->AddCart($cart);
                                }

                                $_SESSION['activeCart'] = serialize($cart);
                                $_SESSION['customer'] = serialize($customer);

                                setcookie('newCartName',"",time()-3600);

                            }

                            if(isset($_POST['cartList'])){
                                $customer = new Customer();
                                if(isset($_SESSION['customer'])){
                                    $customer = unserialize($_SESSION['customer']);
                                }
                                $cartArray = array();
                                $cartArray = $customer->GetSavedCarts();

                                if($_POST['cartList'] == "newuniquecartid1234567890"){
                                    unset($_POST['cartList']);
                                    newCart();
                                }
                                else{   
                                    for($i = 0; $i < sizeof($cartArray); $i++){
                                        if($cartArray[$i]->GetCartID() == $_POST['cartList']){
                                            $_SESSION['activeCart'] = serialize($cartArray[$i]);
                                        }
                                    }
                                }
                            }


                            if(isset($_SESSION['customer'])){
                                $customer = new Customer();
                                $customer = unserialize($_SESSION['customer']);
                                $customer->printCartsList("select-cart","true");
                            }
                            else{
                                $customer = new Customer();
                                $customer->printCartsList("select-cart","true");
                            }
                        ?>

    print '<form method="POST" name="cartSelectForm" action="home.php">';

        print '<select name="cartList" id="' . $id . '" data-mini="' . $mini . '" onchange="submitCartForm()" data-icon="false">';

            print '<option value="newuniquecartid1234567890">*** New Cart ***</option>';


        print '</select>';

    print '</form>';

function submitCartForm(){
    var cookie = getCookie("newCartName");
    if(cookie == null){
        document.cartSelectForm.submit();
    }
}   

if(isset($_POST['cartList'])){
    if($_POST['cartList'] == "newuniquecartid1234567890"){
        unset($_POST['cartList']);
        newCart();
    }
}

function newCart(){

    echo "<script>DisplayInputBox();</script>"; 

}

function DisplayInputBox(){

    // today is defined in the full version of this code (see above if needed)
    var name = prompt("Enter a name for this cart", today);

    if(name != null){

        // Set a cookie containing the name of the new cart
        setCookie("newCartName",name,1);

    }
}

if(isset($_COOKIE['newCartName'])){

    $success = $customer->UpdateCart($cart);

    if($success == false){
        $customer->AddCart($cart);
    }

    setcookie('newCartName',"",time()-3600);

}