用PHP显示jQuery提醒

Question

嗨，我是PHP新手，对我来说一切都非常混乱。我试图做的和失败的是在页面上点击一个按钮时在屏幕上显示一个警报。

我的代码signInFunction.php：

<?php 
if(isset($_POST['signIn'])){ 
    if(isset($_POST['username']) and isset($_POST['password'])){ 
     $username = $_POST['username']; 
     $password = $_POST['password']; 

     ?> 
     <script type="text/javascript">alert("test");</script> 
     <?php 
     echo "username is: ".$username." and password is: ". $password; 
    } 
    else{ 
     echo "Please enter username and password"; 
    } 
} 
else{ 
    echo "error button"; 
} 
?> 

在index.php文件

看起来是这样的：

<?php include "includes/header.php" ?> 
    <?php include "includes/navbar.php" ?> 
    <?php include "includes/carousel.php"?> 
    <?php include "includes/marketing.php"?> 
    <?php include "includes/features.php"?> 
    <?php include "includes/hidden.php"?> 
    <?php include "includes/footer.php" ?> 
    <?php include "includes/functions/signinFunction.php"?> 

的问题是，我管理底部显示的数据，但未能让警报出现..我错过了什么？

Answer 1

<form action="" method="post" > 
    <input name='username' type='text' value=''/> 
    <input name='password' type='text' value='' /> 
    <input type='button' name='signIn' value='Sign In' /> 
</form> 
<?php 
if(isset($_POST['signIn'])){ 
    if(isset($_POST['username']) and isset($_POST['password'])){ 
     $username = $_POST['username']; 
     $password = $_POST['password']; 

     ?> 
     <script type="text/javascript">alert("test");</script> 
     <?php 
     echo "username is: ".$username." and password is: ". $password; 
    } 
    else{ 
     echo "Please enter username and password"; 
    } 
} 
else{ 
    echo "error button"; 
} 
?> 

当U点击按钮符号那么警报应该出现

Answer 2

echo '<script language="javascript">'; 
echo 'alert("alert")'; 
echo '</script>';