javascript中未定义的输入字段值
我正试图将HTML表单中的值发送到javascript文件，但我看到，电子邮件主题和消息的值在警报窗口或控制台中被发送为未定义的值，，而名称则正确地从输入中提取并传输到js，我对javascript非常陌生，所以这个问题可能非常愚蠢，但我无法理解为什么会发送undefined，而且我也不明白当javascript和HTML代码以什么顺序执行时，我有时会看到javascript是在单击按钮之前先执行的 这是存储在临时html中的我的html表单javascript中未定义的输入字段值,javascript,html,Javascript,Html,我正试图将HTML表单中的值发送到javascript文件，但我看到，电子邮件主题和消息的值在警报窗口或控制台中被发送为未定义的值，，而名称则正确地从输入中提取并传输到js，我对javascript非常陌生，所以这个问题可能非常愚蠢，但我无法理解为什么会发送undefined，而且我也不明白当javascript和HTML代码以什么顺序执行时，我有时会看到javascript是在单击按钮之前先执行的 这是存储在临时html中的我的html表单 <!doctype html>
<!doctype html>
<html lang="en">
<head>
<title>Contact Form</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- Material Design Bootstrap -->
<link href="css/mdb.min.css" rel="stylesheet">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css" integrity="sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B" crossorigin="anonymous">
</head>
<body>
<form id="connect-form" method="POST">
<div class="row">
<div class="card-body col-lg-6 col-sm-12 col-md-6">
<div class="md-form mt-3">
<input type="text" id="name" class="form-control" required="required">
<label for="materialContactFormName">Name</label>
</div>
<div class="md-form mb-3" id="email" placeholder="Email">
<input type="text" class="form-control mb-3" id="name" required="required">
<label for="email">Email</label>
</div>
<div class="md-form mb-3" id="subject" placeholder="Subject">
<input type="text" class="form-control mb-3" id="name" required="required">
<label for="subject">Subject</label>
</div>
</div>
<div class="card-body col-lg-6 mt-2 col-sm-12 col-md-6">
<div class="md-form">
<textarea class="form-control md-textarea" name="message" rows="4" id="message"
placeholder="say Hi, and I will probably get back to you in 24 hrs :)" style="resize: none; width: 100%; box-sizing: border-box; height: 100%;" required="required"></textarea>
<label for="message">Message</label>
</div>
</div>
</div>
<div class="form-action" style="text-align: center;margin: auto" >
<button onclick="contactuser()" class="btn btn-elegant btn-block" type="submit" style="height: 50px;width: 50%;" >Submit</button>
</div>
<script type="text/javascript" src="js/file.js"></script>
</form>
</div>
<!-- Bootstrap core JavaScript -->
<script src="vendor/jquery/jquery.min.js"></script>
<script src="vendor/bootstrap/js/bootstrap.bundle.min.js"></script>
<!-- MDB CORE JAVASCRIPT -->
<script type="text/javascript" src="js/mdb.min.js"></script>
<!-- Plugin JavaScript -->
<script src="vendor/jquery-easing/jquery.easing.min.js"></script>
</body>
</html>
html中的ID是unice，您不能对3个输入使用ID=“name”
<!doctype html>
<html lang="en">
<head>
<title>Contact Form</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- Material Design Bootstrap -->
<link href="css/mdb.min.css" rel="stylesheet">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css" integrity="sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B" crossorigin="anonymous">
</head>
<body>
<form id="connect-form" method="POST">
<div class="row">
<div class="card-body col-lg-6 col-sm-12 col-md-6">
<div class="md-form mt-3">
<input type="text" id="name" class="form-control" required="required">
<label for="materialContactFormName">Name</label>
</div>
<div class="md-form mb-3">
<input type="text" placeholder="Email" class="form-control mb-3" id="email" required="required">
<label for="email">Email</label>
</div>
<div class="md-form mb-3">
<input type="text" class="form-control mb-3" id="subject" placeholder="Subject" required="required">
<label for="subject">Subject</label>
</div>
</div>
<div class="card-body col-lg-6 mt-2 col-sm-12 col-md-6">
<div class="md-form">
<textarea class="form-control md-textarea" name="message" rows="4" id="message" placeholder="say Hi, and I will probably get back to you in 24 hrs :)" style="resize: none; width: 100%; box-sizing: border-box; height: 100%;" required="required"></textarea>
<label for="message">Message</label>
</div>
</div>
</div>
<div class="form-action" style="text-align: center;margin: auto">
<button onclick="contactuser()" class="btn btn-elegant btn-block" type="submit" style="height: 50px;width: 50%;">Submit</button>
</div>
<script type="text/javascript" src="js/file.js"></script>
</form>
</body>
<!-- Bootstrap core JavaScript -->
<script src="vendor/jquery/jquery.min.js"></script>
<script src="vendor/bootstrap/js/bootstrap.bundle.min.js"></script>
<!-- MDB CORE JAVASCRIPT -->
<script type="text/javascript" src="js/mdb.min.js"></script>
<!-- Plugin JavaScript -->
<script src="vendor/jquery-easing/jquery.easing.min.js"></script>
</body>
</html>
html中的ID是unice，您不能对3个输入使用ID=“name”
<!doctype html>
<html lang="en">
<head>
<title>Contact Form</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- Material Design Bootstrap -->
<link href="css/mdb.min.css" rel="stylesheet">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css" integrity="sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B" crossorigin="anonymous">
</head>
<body>
<form id="connect-form" method="POST">
<div class="row">
<div class="card-body col-lg-6 col-sm-12 col-md-6">
<div class="md-form mt-3">
<input type="text" id="name" class="form-control" required="required">
<label for="materialContactFormName">Name</label>
</div>
<div class="md-form mb-3">
<input type="text" placeholder="Email" class="form-control mb-3" id="email" required="required">
<label for="email">Email</label>
</div>
<div class="md-form mb-3">
<input type="text" class="form-control mb-3" id="subject" placeholder="Subject" required="required">
<label for="subject">Subject</label>
</div>
</div>
<div class="card-body col-lg-6 mt-2 col-sm-12 col-md-6">
<div class="md-form">
<textarea class="form-control md-textarea" name="message" rows="4" id="message" placeholder="say Hi, and I will probably get back to you in 24 hrs :)" style="resize: none; width: 100%; box-sizing: border-box; height: 100%;" required="required"></textarea>
<label for="message">Message</label>
</div>
</div>
</div>
<div class="form-action" style="text-align: center;margin: auto">
<button onclick="contactuser()" class="btn btn-elegant btn-block" type="submit" style="height: 50px;width: 50%;">Submit</button>
</div>
<script type="text/javascript" src="js/file.js"></script>
</form>
</body>
<!-- Bootstrap core JavaScript -->
<script src="vendor/jquery/jquery.min.js"></script>
<script src="vendor/bootstrap/js/bootstrap.bundle.min.js"></script>
<!-- MDB CORE JAVASCRIPT -->
<script type="text/javascript" src="js/mdb.min.js"></script>
<!-- Plugin JavaScript -->
<script src="vendor/jquery-easing/jquery.easing.min.js"></script>
</body>
</html>
需要为输入元素而不是div指定属性id
函数contactuser（）{
var Name=document.getElementById（“Name”）.value；
var Email=document.getElementById（“Email”）.value；
var subject=document.getElementById（“subject”）.value；
var message=document.getElementById（“message”）.value；
警报（“按钮点击“+”名称：“+名称+”电子邮件：“+电子邮件+”主题：“+主题”）；
}
名称
电子邮件
主题
消息
提交
函数contactuser（）{
var Name=document.getElementById（“Name”）.value；
var Email=document.getElementById（“Email”）.value；
var subject=document.getElementById（“subject”）.value；
var message=document.getElementById（“message”）.value；
警报（“按钮点击“+”名称：“+名称+”电子邮件：“+电子邮件+”主题：“+主题”）；
}
名称
电子邮件
主题
消息
提交
function contactuser(){
var Name = document.getElementById("name").value;
var Email = document.getElementById("email").value;
var subject = document.getElementById("subject").value;
var message = document.getElementById("message").value;
alert("Button Clicked" + "Name: " + Name + "Email:" +Email + " subject:"+ subject);
}