如何延迟表单提交

Question

我正在为我的开始做一个基本的网络表单 Javascript class。我几乎得到了我所有的预期结果（作业包括输入验证和按名称将元素存储在数组中），除了当我提交表单时，我想在我点击提交时延迟 5 秒到页面重定向时。这种延迟是为了让用户能够取消订单。

根据我们目前在 class 中学到的知识，我希望我使用 setTimeout 代码块执行此操作 - 虽然我还没有能够做到这一点。我的表单提交依赖于来自被调用函数的 true/false return 值，我想延迟真正的值不会如此快速地命中。我附上了我的完整 HTML 文件，但我想知道为什么它不起作用的代码块是：

    setTimeout(function() {
                   return true;
               }, 5000);

我在 Chrome 中调试时观察到的第一个问题是，这不会 return 返回周围代码的真值。

我认为 jQuery 可以做一些事情来规避这一点，但我们还没有涵盖任何内容，所以我想避免走那条路。

```
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
    <meta name="description" content="Costello Improved">
    <meta http-equiv="Content-type" content="text/html;charset=UTF-8" />
    <title>Costellos Pasta and Pizza</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
    <link rel="stylesheet" href="costello.css">
</head>

<body>

    <form name="myForm" action="https://costello-pasta.glitch.me/order" id="myForm" method="POST" onsubmit="return calculateOrder(this)">
        <div class="container">

            <div class="row">
                <div class="col-md-12" id="debug">Costello's Online Orders</div>
            </div>

            <div class="row">
                <div class="col-md-4  label">Pasta Bowl</div>
                <div class="col-md-4"> (basic price: .50)</div>
                <div class="col-md-4"></div>
            </div>

            <div class="row">
                <div class="col-md-4  label">Pasta</div>
                <div class="col-md-4">
                    <div><input type="radio" name="pastatype" value="0" />Spaghetti (no extra cost)</div>
                    <div><input type="radio" name="pastatype" value="50" />Fettucine (add 50 cents)</div>
                    <div><input type="radio" name="pastatype" value="75" />Fusilli (add 75 cents)</div>
                </div>
                <div class="col-md-4 msg" id="radioLabel"></div>
            </div>

            <div class="row">
                <div class="col-md-4  label">Sauce</div>
                <div class="col-md-4">
                    <select name="sauce">
                        <option value="0">Pomodoro (no extra cost)</option>
                        <option value="50">Bolognese (add 50 cents)</option>
                        <option value="100">Alfredo (add .00)</option>
                    </select>
                </div>
                <div class="col-md-4"></div>
            </div>

            <div class="row">
                <div class="col-md-4  label">Extras</div>
                <div class="col-md-4">
                    <div><input type="checkbox" name="extras" value="200" />Side salad (add .00)</div>
                    <div><input type="checkbox" name="extras" value="100" />Bread sticks (add .00)</div>
                </div>
                <div class="col-md-4"></div>
            </div>

            <div class="row">
                <div class="col-md-4  label">Name</div>
                <div class="col-md-4"><input type="text" id="name" name="client_name" /></div>
                <div class="col-md-4 msg" id="nameLabel"></div>
            </div>

            <div class="row">
                <div class="col-md-4  label">Phone</div>
                <div class="col-md-4"><input type="text" id="phone" value="" /></div>
                <div class="col-md-4 msg" id="phoneLabel"></div>
            </div>

            <div class="row">
                <div class="col-md-4  label"><input type="submit" value="Order" /></div>
                <div class="col-md-4" id="totalcost"></div>
                <div class="col-md-4 msg" id="submitMessage"></div>
            </div>
        </div>

    </form>

</body>

<script>
    function calculateOrder() {
        var totalCost = 750;

        //Storing Pasta radio buttons into array.  Iterating through array and adding checked selection's value to the total cost. 
        var submitBool = true;
        var pastaArray = document.getElementsByName('pastatype');
        for (var i = 0; i < pastaArray.length; i++) {
            if (pastaArray[i].checked == true) {
                totalCost = totalCost + parseInt(pastaArray[i].value);
            }
            //Validating Pasta input
        }
        if (pastaArray[0].checked == false && pastaArray[1].checked == false && pastaArray[2].checked == false) {
            document.getElementById('radioLabel').innerHTML = "Required field! (You must choose a pasta)";
            submitBool = false;
        } else {
            document.getElementById('radioLabel').innerHTML = "";
        }

        //Storing sauce selection into an array.  Adding price for selected option.
        var sauceArray = document.getElementsByName('sauce');
        totalCost = totalCost + parseInt(sauceArray[0].value);

        //Storing extras selection(s) into an array.  Adding prices for selected options.   
        var extraArray = document.getElementsByName('extras');

        for (var x = 0; x < extraArray.length; x++) {
            if (extraArray[x].checked == true) {
                totalCost = totalCost + parseInt(extraArray[x].value);
            }
        }


        //Validating Name input
        if (document.getElementById('name').value == "") {
            document.getElementById('nameLabel').innerHTML = "Required field!  Enter your name.";
            submitBool = false;
        } else {
            document.getElementById('nameLabel').innerHTML = "";
        }

        //Validating Phone Number Input
        var phone = document.getElementById('phone').value;
        phone = phone.toString();

        if (document.getElementById('phone').value == null) {
            document.getElementById('phoneLabel').innerHTML = "Required field!  Enter your phone number.";
            submitBool = false;
        } else if (phone[3] != "-") {
            document.getElementById('phoneLabel').innerHTML = "Enter in 888-888-8888 format!";
            submitBool = false;
        } else if (phone[7] != "-") {
            document.getElementById('phoneLabel').innerHTML = "Enter in 888-888-8888 format!";
            submitBool = false;
        } else if (phone.length > 12 || phone.length < 12) {
            document.getElementById('phoneLabel').innerHTML = "Enter in 888-888-8888 format!";
            submitBool = false;
        } else {
            document.getElementById('phoneLabel').innerHTML = "";
        }


        //Form runs if input has been valid in all input options
        if (submitBool == false) {

            return false;
        } else if (submitBool == true){
            var preFixed = totalCost / 100;
            var postFixed = preFixed.toFixed(2);


            document.getElementById('totalcost').innerHTML = "Total Bill: $" + postFixed;

            document.getElementById('submitMessage').innerHTML = "Order is being processed, <a>cancel?</a>"

           setTimeout(function() {
               return true;
           }, 5000);
        }

    }

</script>

</html>
```

Answer 1

您可以使用 onSubmit 事件并延迟通常的功能。我创建了一个简单的演示，因此您可以轻松理解它。这里表单提交后会在 5 秒后提交表单，或者如果你点击取消则被取消。

const myForm = document.getElementById('myForm');
myForm.addEventListener('submit', handleSubmit);
var submitTimer;

function handleSubmit(event) {
console.log('submitTimer set');
  event.preventDefault();
  submitTimer = setTimeout(() => {
    this.submit();
    console.log('Submitted after 5 seconds');
  }, 5000)
};
function cancel(){
  clearTimeout(submitTimer);
  console.log('Submit Canceled');
}

<form id="myForm">
  <input type="text" name="name"/>
  <button type="submit">Submit</button>
<button type="button" onclick="cancel()" >Cancel</button>
</form>

Answer 2

setTimeout 函数在指定的毫秒数（在您的例子中为 5000）后调用函数或计算表达式。您在代码中所做的只是 return 一个布尔值，而没有创建通道以在时间流逝后获取值。由于此代码有点 "asynchronous"（需要时间），您可以使用内置的 Promise 函数来获取值。换句话说，您的代码可以重组为如下所示：

getTheBoolValue = () => new Promise((resolve, reject) => {
  setTimeout(function(){
    resolve(true)
  },5000)
})

getTheBoolValue().then(data => console.log(data))

如何延迟表单提交

How to delay form submission

html

javascript

settimeout