如何在php中验证表单？

Question

如何验证此表单。当用户在没有选择选项的情况下提交时，他必须得到一个警报。

我的代码：

echo "<form method='post' id='submit' action='checkresult.php'>";
$sql="SELECT * FROM cquestions where showdate='$today' limit 2";
$result=mysql_query($sql);
while ($row = mysql_fetch_array($result)) {
echo "<p>" . $row['cqtext'] . "</p>";
$sql2="SELECT * FROM canswers where cqid=".$row['cqid'];
$result2=mysql_query($sql2);
while($row2=mysql_fetch_assoc($result2))
{
echo "<input type='radio' name='".$row['cqid']."' value='".$row2['cqans']."' />".$row2['aatext']; }
}

Answer 1

您正在寻找的是 $_POST 变量。当您提交使用 action='checkresult.php' 的表单时，您将能够在 checkresult.php 上使用 $_POST 命令检索变量值。

test.php 页面（使用表单输出的内容）：

<form method='post' id='submit' action='checkresult.php'>
<input type='radio' name='the_name' value='the_value' />
<input type="submit">
</form>

checkresult.php：

echo $_POST["the_name"];
// Output = the_value

Answer 2

你使用的方法是正确的，但语法错误：

<?php
$marks+=$_POST['$cqid']; //Not Correct!
//1st You haven't defined $cqid. Its $qid.
//2nd You can't use a variable inside single quotes.
//PHP will consider it as normal String. But you can use it inside double quotes.
//But remember you can't use array ($row['cqid']) inside double quotes.
?>

---

这是正确的方法：

<?php
while ($row = mysql_fetch_array($result)) {
    //$qid=$row['cqid'];
    //$marks+=$_POST[$qid]; //Correct!
    //But, Not needed You can directly use $row['cqid'] as an index.
    $marks+=$_POST[$row['cqid']];
}
?>

---

更新：[用于调试]

while ($row = mysql_fetch_array($result)) {
    $marks+=$_POST[$row['cqid']];
    echo $marks.'<br/>';
}
$insert="insert into result(email,marks)values('$email',$marks)";
$insert = mysql_query($insert);
if(!$result) {
    die('Unable to perform insert action. The following error occured: '.  mysql_error());
} else {
   echo 'The following Query: <b>'.$insert.'</b> executed successfully!';
}

还要检查$email 的值，我看不出你是从哪里得到这个值的。

而$login_session = $_POST['email']; 这行重复了两次，但我确信这个值总是空的，因为在 test.php 中您已经注释了以下行：

echo "<input type='hidden' name='email' value='email' />";

value属性：value='email'显然好像错了！

检查所有这些，我想你现在可以从这里继续... :) 如果没有，我仍然很乐意帮助你...

更新：[用于设置查询限制]

SELECT * FROM `cquestions` LIMIT 0,3;
//Will fetch first three records from cquestions.
SELECT * FROM `cquestions` LIMIT 2,3;
//Will fetch 3rd, 4th and 5th records from cquestions.