此表单适用于访客登录，您可以从1到9中选择与您一起的访客人数。
当选择“1”并点击提交时，我会继续为“visitorname1”获取未定义的索引。
PHP表格
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Visitor Sign In</title>
<link rel="stylesheet" href="css.css" type="text/css" media="screen" />
<link href="//netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.css" rel="stylesheet">
<meta name="viewport" content="width=device-width">
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" ></script>
<script type="text/javascript">
//when the webpage has loaded do this
$(document).ready(function() {
//if the value within the dropdown box has changed then run this code
$('#noguests').change(function(){
//get the number of fields required from the dropdown box
var num = $('#noguests').val();
var i = 0; //integer variable for 'for' loop
var html = ''; //string variable for html code for fields
//loop through to add the number of fields specified
for (i=1;i<=num;i++) {
//concatinate number of fields to a variable
html += 'Visitor ' + i + ': <input type="text" name="visitorname' + i + '" id="visitorname' + i + '"/><br/>';
}
//insert this html code into the div with id catList
$('#guestList').html(html);
});
});
</script>
</head>
<body>
<p align="center"><img src="images/logo.jpg" width="300"></p>
<h1 align="center">Landmark Group of Builders :: Visitor Sign In</h1>
<table border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td colspan="2"><span class="large">Please sign-in below:</span></td>
</tr>
<form id="form1" name="form1" method="post" action="submit_guest.php">
<tr>
<td bgcolor="#EAEAEA" align="right"><b>Visiting</b></td>
<td bgcolor="#EAEAEA"><input name="visiting" type="text" required id="visiting"></td>
</tr>
<tr>
<td bgcolor="#EAEAEA" align="right"><b>No. of Guests</b></td>
<td bgcolor="#EAEAEA">
<select id="noguests" name="noguests">
<option value="0">- SELECT -</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
</select>
</td></tr>
<td id="guestList">
</td></tr>
</tr>
<tr>
<td colspan="2" align="right">
<input type="text" name="stat" size="40" value="1" readonly class="hidden"><br><input type="submit" value="Sign In" class="css3button"></td>
</tr>
</form>
</table>
</body>
</html>
UPDATE.php
<?php
$intime = date('Y-m-d H:i:s');
$visitorname1 = $_POST['visitorname1'];
$visting = $_POST['visiting'];
$stat = $_POST['stat'];
$noguests = $_POST['noguests'];
$sql = new mysqli('localhost','x','x1!','x1');
$query = $sql->prepare("INSERT INTO `visitors` (visitorname1, visiting, intime, stat, noguests) VALUES (?,?,?,?,?);");
$query->bind_param('sssii',$_POST['visitorname1'],$_POST['visiting'],$_POST['intime'],$_POST['stat'],$_POST['noguests']);
/* close our connection */
$query ->execute();
if ( $query ) {
echo "<p align='center' class='confirmation'><img src='images/logo.jpg' width='300px'><BR><BR><img src='images/accepted.png'> Thank You! You have been signed in!</p>";
} else {
echo "Your request failed. Please try again.";
}
$sql->close();
?>
当我通过选择“1”添加文本框时，我不确定为什么我继续获取未定义的文本框，文本框的ID和名称为“visitorname1”。
非常感谢任何帮助。
答案 0 :(得分：0)
删除var i = 0;和：
改变你的：
for (i=1;i<=num;i++) {
到
for (var i = 0;i<=num;i++) {
答案 1 :(得分：0)
因为您的动态输入没有value属性。
答案 2 :(得分：0)
在javascript中，您将NAME设置为name =“visitorname”，而在PHP中，您有$ _POST ['visitorname1'];
解决方案：将PHP更改为$ _POST ['visitorname'];
答案 3 :(得分：0)
这是因为在错误的地方使用Form标签！ 像这样纠正你的HTML代码
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Visitor Sign In</title>
<link rel="stylesheet" href="css.css" type="text/css" media="screen" />
<link href="//netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.css" rel="stylesheet">
<meta name="viewport" content="width=device-width">
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" ></script>
<script type="text/javascript">
//when the webpage has loaded do this
$(document).ready(function() {
//if the value within the dropdown box has changed then run this code
$('#noguests').change(function(){
//get the number of fields required from the dropdown box
var num = $('#noguests').val();
var i = 0; //integer variable for 'for' loop
var html = ''; //string variable for html code for fields
//loop through to add the number of fields specified
for (i=1;i<=num;i++) {
//concatinate number of fields to a variable
html += 'Visitor ' + i + ': <input type="text" name="visitorname' + i + '" id="visitorname' + i + '"/><br/>';
}
//insert this html code into the div with id catList
$('#guestList').html(html);
});
});
</script>
</head>
<body>
<p align="center"><img src="images/logo.jpg" width="300"></p>
<h1 align="center">Landmark Group of Builders :: Visitor Sign In</h1>
<form id="form1" name="form1" method="post" action="submit_guest.php">
<table border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td colspan="2"><span class="large">Please sign-in below:</span></td>
</tr>
<tr>
<td bgcolor="#EAEAEA" align="right"><b>Visiting</b></td>
<td bgcolor="#EAEAEA"><input name="visiting" type="text" required id="visiting"></td>
</tr>
<tr>
<td bgcolor="#EAEAEA" align="right"><b>No. of Guests</b></td>
<td bgcolor="#EAEAEA">
<select id="noguests" name="noguests">
<option value="0">- SELECT -</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
</select>
</td></tr>
<td id="guestList">
</td></tr>
</tr>
<tr>
<td colspan="2" align="right">
<input type="text" name="stat" size="40" value="1" readonly class="hidden"><br><input type="submit" value="Sign In" class="css3button"></td>
</tr>
</table>
</form>
</body>
</html>