我的项目的这个特定页面显示了存储在数据库中的问题列表。用户需要选择 10 个问题，然后单击按钮进行测验。我可以将复选框选择限制为 10 个问题，并确保选择的问题不少于 10 个。例如，如果用户选择了 5 个问题，则会弹出警报，通知用户需要选择 10 个问题，但随后表单会定向到其“操作”位置。如果选择的问题少于 10 个，如何停止提交表单？这是我的代码...
<?php
session_start();
// Insert header
if ('Header.php') {
include 'Header.php';
} else {
echo "The file was not found";
}
// Define database info
$username = "";
$password = "";
$servername = "localhost";
// Connect to database and display all
// questions with check boxes to allow user
// to select a max of 10 questions.
try {
$pdo = new PDO("mysql:host=$servername; dbname=Quizes", $username, $password);
// Set the PDO error mode to exception
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
// Query to select all questions
$sql_selectQuestions = "SELECT * FROM QuestionTable";
$result_selectQuestions = $pdo->query($sql_selectQuestions);
$questionList = $result_selectQuestions->fetchAll();
} catch (PDOException $e) {
echo "Connection failed: " . $e->getMessage();
}
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Question Selection</title>
<script type="text/javascript">
chkcontrol = function(j) {
var total = 0;
var questions = document.getElementsByName('questions[]');
for (var i = 0; i < questions.length; i++) {
if (questions[i].checked) {
total = total + 1;
}
if (total > 10) {
alert("Please select only 10 questions");
questions[i].checked = false;
return false;
}
}
}
chkmin = function() {
var total;
var questions = document.getElementsByName('questions[]');
for (var i = 0; i < questions.length; i++) {
if (questions[i].checked) {
total = total + 1;
}
if (total < 10) {
alert("Please select 10 questions");
return false;
}
}
}
</script>
</head>
<body>
<?php echo "<br />"; ?>
<form id="questionselect" name="questions" action="ChooseQuizTime.php" method="post">
<table border="2" style="margin:0 auto; padding:5px">
<thead>
<tr>
<th>Question Number</th>
<th>Questions</th>
<th>Include in Quiz</th>
</tr>
</thead>
<tbody>
<?php
// Print a row for each record in the returned query
foreach($questionList as $key => $row)
{
echo "
<tr>
<td style='text-align:left;'>$row[questionId]</td>
<td style='text-align:left;'>$row[questionText]</td>
<td style='text-align:center;'><input type='checkbox' name='questions[]' onclick='chkcontrol($count)' value='$row[questionId]' /></td>
</tr>";
}
?>
</tbody>
</table>
<div align="center">
<br />
<input type="submit" value="Take Quiz" onclick="chkmin()" />
</div>
</form>
</body>
</html>
最佳答案
尝试使用表单的 onsubmit 属性:
<form id="questionselect" name="questions" action="ChooseQuizTime.php" method="post" onsubmit="return chkmin($count);">
关于javascript - 如何停止提交并提醒用户用JS选择的问题少于10个问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37420311/