PHP 错误表单 - 将表单的内容保留在重定向上

我有一个简单的登录表单，如果发生错误（例如密码错误），我需要它能够记住输入的用户名。 我会继续做这个PHP或Javascript，因为我不允许使用JQuery。

我当前的PHP - （不包括HTML表单）

<?php
//MySQl Connection
 mysql_connect("localhost", "root", "") or die(mysql_error()); 
 mysql_select_db("clubresults") or die(mysql_error()); 
//Initiates New Session - Cookie
session_start(); // Start a new session
// Get the data passed from the form
$username = $_POST['username'];
$password = md5($_POST['pass']);
// Do some basic sanitizing
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);
//Performs SQL Query to retrieve Login Details from DB
$sql = "select * from admin_passwords where username = '$username' and password = '$password'";
$result = mysql_query($sql) or die ( mysql_error() );
//Assigns a Variable Count to 0
$count = 0;
//Exectues a loop to increment on Successful Login
while ($line = mysql_fetch_assoc($result)) {
     $count++;
}
//If count is equal to 1 Redirect user to the Members Page and Set Cookie
if ($count == 1) {
     $_SESSION['loggedIn'] = "true";
     header("Location: members.php"); // This is wherever you want to redirect the user to
} else {
//Else Echo that login was a failure.
die('Login Failed. <a href=login.php>Click Here to Try Again</a>');
}
?>

任何帮助将不胜感激。干杯