if($username!="")
{
mysql_connect("localhost", "root", "");
mysql_select_db("mydata") or die ("不能连接到数据库!");
//判断用户名和密码是否在正确
$strSql="select * from maildata where yhm='$username' and mm='$password'";
$result=mysql_query($strSql);// or die("读取数据库出现错误!");
$xm = select xm from maildata where yhm='$username' and mm='$password';
$num=mysql_num_rows($result);
mysql_close($myconn);
if($num>0)
{ echo "<center>当前用户为<b>$xm</b> 欢迎光临</center>";
echo "login.php?username=".$username;