Question

我编写了一个代码，用于在不使用AJAX的情况下在HTML段落标记中的某个特定位置显示返回变量值。

我为此编写了以下代码，但它不适用于我。

<?php
$Success = "";
$Failed = "";
?>

<br><br>

<center>
    <h3>Already a user? Log in:</h3>
    <p style="color:green;"><?php echo $Success; ?></p>
    <p style="color:red;"><?php echo $Failed; ?></p>
    <form action="" method="POST">
        <div>Username:</div> <input type="text" name="username">
        <div>Password:</div> <input type="password" name="password">
        <br><br>
        <input type="submit" value="Log In" name="login">
    </form>
</center>

<?php
if(isset($_POST['login']))
{
    if( !empty($_POST['username']) && !empty($_POST['password']) )
    {
        $Success = "Thanks.";
    }
    else
    {
        $Failed = "You must supply a username and password.";
    }
}
?>

Answer 1

Php脚本逐行编译，因此您必须在使用之前分配变量。你可以用这个：

<?php
$Success = "";
$Failed = "";

if(isset($_POST['login']))
{
    if( !empty($_POST['username']) && !empty($_POST['password']) )
    {
        $Success = "Thanks.";
    }
    else
    {
        $Failed = "You must supply a username and password.";
    }
}
?>

<br><br>

<center>
    <h3>Already a user? Log in:</h3>
    <p style="color:green;"><?php echo $Success; ?></p>
    <p style="color:red;"><?php echo $Failed; ?></p>
    <form action="" method="POST">
        <div>Username:</div> <input type="text" name="username">
        <div>Password:</div> <input type="password" name="password">
        <br><br>
        <input type="submit" value="Log In" name="login">
    </form>
</center>

在某些地方显示php变量的值

1 个答案: