session 启动失败后 PHP 重定向

Question

我设法在“checklogin.php”执行后启动 session ，但当我尝试重定向到“login_success.php”时，我仍保留在同一“checklogin.php”页面上。您对我能做什么有什么建议吗？

<?php

    ob_start();
    $host="";
    $username="";
    $password="";
    $db_name="";
    $tbl_name="";

    // Connect to server and select databse.
    mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
    mysql_select_db("$db_name")or die("cannot select DB");

    // username and password sent from form 
    $myusername=$_POST['myusername']; 
    $mypassword=$_POST['mypassword']; 

    // To protect MySQL injection (more detail about MySQL injection)
    $myusername = stripslashes($myusername);
    $mypassword = stripslashes($mypassword);
    $myusername = mysql_real_escape_string($myusername);
    $mypassword = mysql_real_escape_string($mypassword);
    $sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";
    $result=mysql_query($sql);

    // Mysql_num_row is counting table row
    $count=mysql_num_rows($result);

    // If result matched $myusername and $mypassword, table row must be 1 row
    if($count==1){

    // Register $myusername, $mypassword and redirect to file "login_success.php"
    session_start();
    $_SESSION['myusername']=$myusername;
    $_SESSION['mypassword']=$mypassword;
    header("location:login_success.php");
    }
    else {
    echo "Wrong Username or Password. Please try again.";
    }
    ob_end_flush();

    ?>

我收到以下错误:

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /homepages/46/d473160420/htdocs/checklogin.php:58) in /homepages/46/d473160420/htdocs/checklogin.php on line 93

Warning: Cannot modify header information - headers already sent by (output started at /homepages/46/d473160420/htdocs/checklogin.php:58) in /homepages/46/d473160420/htdocs/checklogin.php on line 96

Answer 1

我刚刚发现我将 php 代码放在了 HTML 中。我将它放在文档的顶部，现在它可以工作了。