php头不是在线工作，而是在我的本地主机上工作……为什么？

这在我的本地主机上运行得非常好，但当我在线托管时，它不会登录，并且会成功无误地回显登录。请问这是什么原因

<?php
session_start();
           $_SESSION['user_logged']=$user;
             $_SESSION['user_password']=$password;
                      $user = $_POST["username"];    
                        $password = $_POST["password"];


include("include/connect.php");
$msg = array();

if(isset($_POST['submit'])){

foreach($_REQUEST as $key=>$val){
 $$key=$val;
}

if(count($msg)==0){

$sql="SELECT username, password FROM admin WHERE username='$username' && password='$password'";
$res=mysql_query($sql) OR die(mysql_error());
    if(mysql_fetch_array($res)>0){
    $_SESSION['user_logged']= $user;
    $_SESSION['user_password']=$password;   
    header("location:dashboard.php");
    echo "You looged in Successfully";
    }  else{
    $msg[]='Incorrect username/password';
    }

 }

    } 
 ?>

下面是dashboard.php，它应该重定向到该dashboard.php

 <?php 
 include('include/connect.php');
 include('include/function.php');
 if(isset($_REQUEST['mode']) )
    {
  $mode=$_REQUEST['mode'];
if($mode == 1)
{
     $id=$_REQUEST['id'];
     $sql="DELETE FROM enquiry WHERE id='$id'";
     $result=mysql_query($sql);
    }
   }
 $msg=array();
 if(isset($_POST['submit'])){

$title=$_POST['news'];
$news_item=$_POST['news'];
if(empty($news_item)){
    $msg[]='You must enter news in the column!';
}
if(empty($title)){
    $msg[]='News Title must not be empty!';
}

    else {

    $sql = "SELECT * FROM news_file WHERE title='$title' ";
$res = mysql_query($sql) or die(mysql_error());
$result = mysql_fetch_array($res);
if($result > 0){
    $msg[] = 'News with the same title has been added already';

}  else {

 $sql = "INSERT INTO news_file (title,news,date) VALUES ('$title','$news_item',Now())";
     $result = mysql_query($sql);   

     $msg[]='News was successfully added';

}

}

 }
 ?>

试试这个

<?php
session_start();
    /*
        These should be the other way round, as you are setting
        the session variables with variables which have not been
        initialised yet
    */
    $user = $_POST["username"];    
    $password = $_POST["password"];
    $_SESSION['user_logged']=$user;
    $_SESSION['user_password']=$password;

include("include/connect.php");
$msg = array();

if(isset($_POST['submit'])){

foreach($_REQUEST as $key=>$val){
 $key=$val; // Removed Erroneous double $
}

if(count($msg)==0){

$sql="SELECT 
        username, 
        password 
      FROM 
        admin 
      WHERE 
        username='$username' 
      AND 
        password='$password'"; 
      // MySql does not accept && as a comparison operator.
$res=mysql_query($sql);
if(!$res)
{
    var_dump(mysql_error());
    exit;
}
else
{

    if(mysql_fetch_array($res)>0)
    {
        $_SESSION['post'] = $_POST;
        while(mysql_fetch_array($res)>0)
        {
            $_SESSION['user_logged']= $user;
            $_SESSION['user_password']=$password;   
            header("location:dashboard.php");
            echo "You logged in Successfully";
        }
    }
    else
    {
        msg[]='Incorrect username/password';
    }
}
?>

查看您为dashboard.php提供的代码，您希望重定向到的页面会有$\u POST数据。如果您已重定向到该页面，则不会有$\u POST数据可供您从服务器检索

我已经修改了上面的脚本，在会话中存储$_POST数据，因此使用它，您应该能够通过调用$_session['POST']['news']调用您的新闻项目，或者如果这太冗长，只需在dashboard.php脚本中重新分配POST数据，就像这样

$post=$\会话['post']

---

然后您可以使用$post['news']调用它。

重定向后为什么会有echo语句？你觉得这样对吗？我只想用它来检查是否真的发生了什么，因为页面只是重新加载并停留在登录表单上。感谢与本地主机相比，您在Live Server上使用的PHP版本是什么？mysql_connect函数已经被弃用，应该用PDO或类似的函数替换。但是我在代码的其他部分使用了相同的mysql_connect，它可以工作。这也很有效，只是标题没有很好地重定向。我对此感到厌倦，它只加载一个空页面，而不进入仪表板。仪表板上的会话变量对您可用吗？如果不了解仪表板的功能，就很难解决问题的原因。我已将dashboard.php添加到脚本中，其中的标题应该重定向到该脚本。请任何对此有任何帮助的人，如果有人能够解决，将不胜感激。谢谢，我现在已经为你修改了我的答案。请让我知道这是否有帮助。