緊急！セッションの問題

<?php	session_start();	//使用session存储用户信息	if(isset($_POST["username"]))	{		$ss_user_id="";				//利用User累的IsValid()方法判断所输入的用户名和口令是否正确		require_once("user/UserClass.php");		$user=new User();		//如果正确，转到系统首页		if($user->IsValid($_POST["username"],$_POST["password"],$ss_user_id))		{			$_SESSION["ss_user_id"]=$ss_user_id;			echo "<script language='javascript'>";			echo " location='index.html';";			echo "</script>";		}		//如果不正确，转到登陆页面		else		{			echo "<script language='javascript'>";			echo " alert('用户名或密码错误');";      		echo "</script>";		}	}?>

<?php	include 'http://localhost/gyjw/index.html&fun=000';?>//省略html部分

<?php  	if(! isset($_SESSION['ss_user_id']))	{   		echo "<script language='javascript'>";		echo "alert('您的用户无权进行此操作!');";		echo "top.location='login.html';";		echo "</script>"; 		exit;  	}?>

<?php	include ("check.php");?>