我还是 php 新手，正在努力学习。我有以下代码，变量 $username 和 password 没有被设置，我 99% 确信它们没有问题。
你能指导我做些什么来解决这个问题。每次我运行脚本时，我都会收到用户名和密码未设置消息（使用 if 语句设置）。
<?php
require 'connect.inc.php';
if (isset($_POST['login_button'])&&($_POST['username'])&&($_POST['password'])){
$login_button = $_POST['login_button'];
$username = $_POST['username'];
$password = $_POST['password'];
$password_hash = md5($password);
if(!empty($username)&&!empty($password)){
$sql = "SELECT `id` FROM `golden_acres_username` WHERE `uname`='$username' AND `password`='$password_hash'";
if($sql_run = mysql_query($sql)){
$query_num_rows = mysql_num_rows($sql_run);
}
if($query_num_rows==0){
echo mysql_result($sql_run);
}
else if($query_num_rows==1){
echo 'ok';
}
} else {
echo 'You must supply a username and a password.';
}
}
else {
echo $array;
echo 'Username and password are not set';
}
?>
<form class="home_logon_area" action="" method="POST">
<table border="0">
<tr><td colspan="2">Username: </td></tr>
<tr><td colspan="2"><input type="text" class="text_field" name="username" size="30"/></td></tr>
<tr><td colspan="2">Password: </td></tr>
<tr><td colspan="2"><input type="password" class="text_field " type="password" name="password" size="30"/></td></tr>
<tr><td valign="top"><a class="home_content_link_form" href="no_password.html"> Forgor Password </a></td>
<td align="right" rowspan="2"><input type="submit" name="login_button" id="login_button" value="Login"/></td></tr>
<tr><td><a class="home_content_link_form" href="register.php"> Register </a></td></tr>
</table>
</form>
?>
提前致谢，
约瑟夫