Javascript 403 PHP登录中禁止的错误

每当我点击我登录的提交按钮时，我会看到一个空白页面，上面有“403禁止”，我觉得这可能是因为我的登录页面的URL是“mywebsite.com8:8888/login/”，并且托管在不同的端口上（我使用的是Tornado web服务器）

HTML

 <form method="POST">
      <fieldset id="inputs">
        <input name="username" id="username" required>   
        <input name="password" id="password" type="password" name="Password" placeholder="Password" required>
      </fieldset>
      <fieldset id="actions">
        <input type="submit" id="submit" value="Log in" name="submit">
        <label><input type="checkbox" checked="checked"> Keep me signed in</label>
      </fieldset> 
     </form> <div id="container"></div>

让我登录

PHP

<?php header('Access-Control-Allow-Origin: *'); ?>
<?php
if (isset($_POST['submit'])){
session_start(); 
error_reporting(0); 

    $username = $_POST['username'];
    $password = md5($_POST['password']);

        $connection = mysql_connect("localhost", "moot", "lmlkmklmklmkl"); // Establishing Connection with Server
$db = mysql_select_db("snamr", $connection); // Selecting Database from Server
        $sql="SELECT * FROM accs WHERE name='$username' and password='$password'";
$result=mysql_query($sql);

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
$check = mysql_query("SELECT active FROM accs WHERE name = '$username'");
while($rows=mysql_fetch_assoc($check)){
      $active = $rows['active'];
}

// If result matched $myusername and $mypassword, table row must be 1 row
if($count!=1){
echo "Wrong Username or Password";
}
elseif ($active == 0) {
echo "Your account isn't active!";
}
else {
    $_SESSION['username'] = $username; 
}
$time = time();
$setLogged= mysql_query("UPDATE accs SET loginstatus = '$time' WHERE name = '$username'") or die(mysql_error());
}
}
?>

JS不会从不同的来源加载网站，除非你知道，php实际上会加载到网页中，因为我已经检查了Google Chrome控制台，并更改了php，在网页上生成随机数，它可以工作。或者我遗漏了什么？因此您提交到同一页面，因为您没有操作：
，即发布到html页面。将URL添加到formI added action=“”的action属性中登录成功，但当我将其指向实际的“/room/1”时，我收到了相同的错误。
    <script type="text/javascript">     
$(document).ready(function(){
    $("#container").load('http://mywebsite.com/sname/signing.php');
  });
</script>