主要 PHP/MySQL 登录项目，带有会话变量

好吧，这两天我一直在网上搜寻并尽力搭建一个相当复杂的登录系统。我已经让它的核心工作起来了，用户可以注册并登录。我对简单的 php 和 mysql 并不陌生，但是当涉及到像这样的深入代码时，我迷失了。基本上我想要的是让用户输入他们的登录名，然后对其进行验证（显然），我已经完成了，然后被重定向到仅显示与其用户名/帐户相关的信息的会员页面。我已经在 checklogin.php 上注册了一些会话变量（我验证登录的文件，请看下面），但我一生都无法将变量传递到实际的会员页面。所以我想我应该从简单的开始。我只是尝试转移用户名并显示一条欢迎消息“你好，[用于在此处登录的用户名]。我无法做到这一点。有人可以帮助我吗？一旦我得到这个，我就可以从那里开始。

登录表单（只是片段）：

<form class="form-signin" role="form" method="post" action="checklogin.php">
         <center><img src="logo.png" style="padding-bottom: 10px;"></center>
         <input type="text" name="myusername" id="myusername" class="form-control" placeholder="Email address"  required autofocus><br>
         <input type="password" name="mypassword" id="mypassword" class="form-control" placeholder="Password"  required>
         <br>
         <button class="btn btn-lg btn-primary btn-block" name="Submit" type="submit">Sign In</button>                  
         </form>

检查登录

<?php
            session_start();
            $host="localhost"; // Host name 
            $username="username"; // Mysql username 
            $password="********"; // Mysql password 
            $db_name="joinfbla_services"; // Database name 
            $tbl_name="members"; // Table 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");

            // Define $myusername and $mypassword 
            $myusername=$_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['myusername'] = $_POST['myusername'];
            $_SESSION['mypassword'] = $_POST['mypassword'];
            echo '<META http-equiv="refresh" content="1;URL=http://joinfbla.com/2014/members/services.php">';
            }

            else {
            echo "Wrong Username or Password";
            }
        ?>

会员页面：

<div class="col-md-4">
            <div class="panel panel-primary">
              <div class="panel-heading">Hello, <?php session_start(); echo $_SESSION['user']?>!</div>
              <div class="panel-body">
                <u><b>BAA Username:</b></u> [Insert PHP/MySQL Here]
                <br>
                <u><b>BAA Password:</b></u> [Insert PHP/MySQL Here]
                <br>
                <u><b>Point's Recorded:</b></u> [Insert PHP/MySQL Here]
                <br>
                <div class="alert alert-warning">Note: Only seniors get points this year, if that field is blank do not fear.</div>
              </div>
            </div>
            <div class="panel panel-primary">
              <div class="panel-heading">This Month in FBLA!</div>
              <div class="panel-body">
                [insert gcalendar here]
              </div>
            </div>
          </div>

我立即注意到一件事，但可能无法完全解决问题：

echo $_SESSION['user']

应该

echo $_SESSION['myusername']