我google了很多来解决这个问题，很遗憾我找不到解决方案为什么要下载php文件而不是执行。当用户提交登录按钮时，
调用的下一个php（meine_daten.php）文件 <form action="php_file_that_is_downloaded_insted_of_being_executed.php" method=post>
标签已下载 这个问题涉及一个特定的PC。 我已经使用本地服务器（XAMPP）（display_errors = on php.ini）和（https://validator.w3.org/）修复了PHP erorrs和bug。
PHP标头设置=＆gt; 内容类型：text / html 。我想知道为什么我家里或其他地方的所有其他电脑都工作正常，但不是在这台特定的电脑上。怎么可能？
有人有什么想法吗？它是否可能是防火墙，不允许执行PHP脚本？但是index.php会在这台电脑上执行！下载发生在用户单击提交按钮并且<form>标记调用脚本meine_daten.php时，在此过程中发生了某些事情，以便下载文件meine_daten.php。
PS：我使用的是Internet Explorer，firefox，Chrome，他们都在这台电脑上下载了php文件
的index.php：
<?php
session_start();
if (isset ( $_SESSION ['BRollenID'] )){
session_unset ();
$_SESSION ['BRollenID'] = null;
session_destroy ();
}
header ( 'Content-Type: text/html; charset=utf-8' );
?>
<!DOCTYPE html>
<html lang="de">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- The above 3 meta tags *must* come first in the head; any other head content must come *after* these tags -->
<meta name="description" content="">
<meta name="author" content="">
<link rel="shortcut icon" href="pics/symbole/favicon.ico">
<title>Login</title>
<!-- Bootstrap core CSS -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
<link href="css/login/ie10-viewport-bug-workaround.css" rel="stylesheet">
<!-- Custom styles for this template -->
<link href="css/login/signin.css" rel="stylesheet">
</head>
<body>
<div class="container">
<form class="form-signin" action="meine_daten.php" method="post">
<h2 class="form-signin-heading">BENUTZER-LOGIN</h2>
<label for="inputEmail" class="sr-only">Email address</label>
<input type="email" id="inputEmail" name="email" class="form-control" placeholder="E-Mail"
required autofocus>
<label for="inputPassword" class="sr-only">Password</label>
<input type="password" id="inputPassword" name="pass" class="form-control" placeholder="Passwort"
required>
<button class="btn btn-lg btn-primary btn-block" type="submit">Login</button>
<a href="neuer_zugang.php" class="btn btn-lg btn-primary btn-block" role="button">Neuer Benutzer</a>
<div style="text-align: center; margin-top: 10px">
<a href="kennwort_vergessen.php" role="button">Kennwort vergessen</a>
</div>
</form>
</div>
<div style="text-align: center">
<img src="pics/logos/logo_tchibo.png" alt="DB Schenker Logo">
</div>
<!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
<script src="js/login/ie10-viewport-bug-workaround.js"></script>
</body>
</html>
meine_daten.php：
<!DOCTYPE html>
<html lang="de">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<meta name="description" content="">
<meta name="author" content="">
<link rel="shortcut icon" href="pics/symbole/favicon.ico">
<title>Meine Daten</title>
<!-- Bootstrap core CSS -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<link href="css/main/jasny-bootstrap.min.css" rel="stylesheet">
<!-- Custom styles for this template -->
<link href="css/main/navmenu.css" rel="stylesheet">
</head>
<?php
header ( 'Content-Type: text/html; charset=utf-8' );
session_start ();
require 'user_check.php';
?>
<body>
<div class="container" style="margin-top: 15px">
<img src="pics/logos/logo_tchibo.png" alt="Logo Tchibo">
<img src="pics/logos/logo_schenker.png" alt="Logo DB Schenker">
</div>
<div class="navmenu navmenu-default navmenu-fixed-left offcanvas-sm">
<a class="navmenu-brand visible-md visible-lg" href="#">Open Filing System</a>
<ul class="nav navmenu-nav">
<?php require 'load/load_navigation.php'?>
<script type="text/javascript">
document.getElementById("meine_daten").className = "active";
</script>
</ul>
</div>
<div class="navbar navbar-default navbar-fixed-top hidden-md hidden-lg">
<button type="button" class="navbar-toggle" data-toggle="offcanvas" data-target=".navmenu">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Tchibo</a>
</div>
<div class="container">
<div class="page-header">
<h1>Meine Daten</h1>
</div>
<form class="form-horizontal" action="send/setangaben.php" method="post">
<?php require 'load/load_meine_daten.php';?>
<div class="row">
<div class="form-group" style="text-align: center;">
<button type="submit" class="btn btn-default">Angaben ändern</button>
<button type="submit" class="btn btn-default">Abbruch</button>
</div>
</div>
</form>
<form action="send/setpass.php" method="post">
<div class="form-group">
<label class="control-label col-sm-2" for="pwd_aktuell">Aktuelles Passwort</label>
<div class="col-sm-10">
<input type="password" class="form-control" id="pwd_aktuell" placeholder="aktuelles Passwort">
</div>
</div>
<div class="form-group">
<label class="control-label col-sm-2" for="pwd_neu">Neues Passwort</label>
<div class="col-sm-10">
<input type="password" class="form-control" id="pwd_neu" placeholder="neues Passwort">
</div>
</div>
<div class="form-group">
<label class="control-label col-sm-2" for="pwd_bestaetigen">Neues Passwort bestätigen</label>
<div class="col-sm-10">
<input type="password" class="form-control" id="pwd_bestaetigen"
placeholder="neues Passwort bestätigen">
</div>
</div>
<div class="row">
<div class="form-group" style="text-align: center;">
<button type="submit" class="btn btn-default">Passwort ändern</button>
<button type="submit" class="btn btn-default">Abbruch</button>
</div>
</div>
</form>
</div>
<!-- Bootstrap core JavaScript
================================================== -->
<!-- Placed at the end of the document so the pages load faster -->
<script src="js/main/jquery-1.10.2.min.js"></script>
<script src="js/main/jasny-bootstrap.min.js"></script>
</body>
</html>