我在下面有一个教师登录页面，教师在其中输入他们的用户名和密码，如果输入的详细信息有效，它将检查数据库。下面是代码:
<body>
<?php
$username="xxx";
$password="xxx";
$database="mobile_app";
mysql_connect('localhost',$username,$password);
@mysql_select_db($database) or die( "Unable to select database");
foreach (array('teacherusername','teacherpassword') as $varname) {
$$varname = (isset($_POST[$varname])) ? $_POST[$varname] : '';
}
?>
<form action="<?php echo htmlentities($_SERVER['PHP_SELF']); ?>" method="post" id="teachLoginForm">
<p>Username</p><p><input type="text" name="teacherusername" value="<?php echo $teacherusername; ?>" /></p> <!-- Enter Teacher Username-->
<p>Password</p><p><input type="password" name="teacherpassword" value="<?php echo $teacherpassword; ?>" /></p> <!-- Enter Teacher Password-->
<p><input id="loginSubmit" type="submit" value="Login" name="submit" /></p>
</form>
<?php
if (isset($_POST['submit'])) {
$query = "
SELECT * FROM Teacher t
WHERE
(t.TeacherUsername = '".mysql_real_escape_string($teacherusername)."')
AND
(t.TeacherPassword = '".mysql_real_escape_string($teacherpassword)."')
";
$num = mysql_num_rows($result = mysql_query($query));
$loged = false;
session_start();
while($row = mysql_fetch_array($result))
{
if ($_POST['teacherusername'] == ($row['TeacherUsername']) && $_POST['teacherpassword'] == ($row['TeacherPassword']))
{
$loged = true;
}
$_SESSION['teacherforename'] = $row['TeacherForename'];
$_SESSION['teachersurname'] = $row['TeacherSurname'];
}
if ($loged == true){
header( 'Location: menu.php' ) ;
}else{
echo "The Username or Password that you Entered is not Valid. Try Entering it Again.";
}
mysql_close();
}
?>
</body>
我的问题是，如果用户获取的登录详细信息不正确并提交，我如何获取它以便它删除密码文本框中的密码，使文本框为空，以便用户重新输入密码。
此外，如果用户刷新浏览器，我希望用户名文本框和密码文本框都变为空白。这可能吗？
谢谢
最佳答案
您在以下行中明确设置了密码字段的值:
<input type="password" name="teacherpassword" value="<?php echo $teacherpassword; ?>" />
如果您只是将 value 属性留空，或者将其完全删除，那么在尝试登录失败后它应该会返回空白。像这样:
<input type="password" name="teacherpassword" />
现在，您的 PHP 脚本有些奇怪:您似乎在仔细检查登录信息，这是不必要的。首先，您检查数据库中传递的凭据匹配的行。之后，循环结果，并再次检查返回的值是否与发布的数据匹配。这最后一步似乎是不必要的!因此，您可以将整个 while(){} block 替换为:
if($num == 1) { // there should be one one user per username
$row = mysql_fetch_array($result);
$_SESSION['teacherforename'] = $row['TeacherForename'];
$_SESSION['teachersurname'] = $row['TeacherSurname'];
$loged = true;
}
关于php - 如何让文本框变回空白，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9129532/