php无刷新登陆

1. <form action="login.php" method="post"  target="userlogin" name="loginform"> 
2. <div class="TxtUser" id="userlogindiv"> 
3. 用户名：<input name="accounts" id="accounts" type="text"   size="18" > 
4. 密码： <input name="passwords" id="passwords"  type="password"  size="18" > 
5. <input type="submit" name="Submit" value="登录" /> 
6. </div> 
7. </form> 
8. <iframe name="userlogin" width="1" height="1" ></iframe> 
9. //login.php页面: 
10. <? 
11. $accounts=$_POST['accounts']; 
12. $passwords=$_POST['passwords']; 
13. $showdata="我登录啦!!"; 
14. if($accounts=="admin" && $passwords=="123456") 
15. { 
16. echo'<script language="JavaScript"> '; 
17. echo'parent.document.getElementById("userlogindiv").innerHTML=''.$showdata.'';'; 
18. echo'</script>'; 
19. } 
20. ?>