login-page.php:<?php 
    require_once 'D:/xampp/php/Smarty/libs/Smarty.class.php'; $smarty = new Smarty();
$smarty->template_dir = "D:/xampp/php/Smarty/demo/templates";
$smarty->compile_dir = "D:/xampp/php/Smarty/demo/compile_dir";
$smarty->config_dir = "D:/xampp/php/Smarty/demo/configs";
$smarty->cache_dir = "D:/xampp/php/Smarty/demo/cache";
    
    
    ob_start();
?>
<form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']);?>" method="post">
    <table>
       <tr>
          <td>用户名</td>
          <td><input type="text" name="UserName" 
           value="<?php isset($_POST['UserName']) ? htmlspecialchars($_POST['UserName']) : '';?>"/></td>
       </tr>
       <tr>
          <td>密码</td>
          <td><input type="password" name="UserPassword" size="20"/></td>
       </tr>
       <tr id="btn">
          <td><input type="submit" name="Login" value="提交"/></td>
          <td><input type="reset" name="Reset" value="重置"/></td>
       </tr>
    </table>
</form>
<?php
$loginForm = ob_get_clean();
    

if (!isset($_POST['Login'])) {
$smarty->assign('contents', $loginForm);
$smarty->display('contents-template.tpl');
}
else {
if (isset($_POST['UserName']) && isset($_POST['UserPassword'])) {
header('Location: php/login-process.php');
exit();
}
else {
$smarty->assign('contents', $loginForm);
$smarty->display('contents-template.tpl');
}
}
?>
contents-template.tpl:
{include file="D:/xampp/php/Smarty/demo/templates/header.tpl"}{$contents}{include file="D:/xampp/php/Smarty/demo/templates/footer.tpl"}为什么没有填用户名与密码直接提交却也进入php/login-process.php?