用户登录验证例题用的ajax

1.登录页面

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title>无标题文档</title>

<script src="jquery-1.11.2.min.js"></script>

</head>

<body>

<div>用户名:<input type="text" id="uid" /></div>

<div>密&nbsp;码:<input type="password" id="pwd" /></div>

<div><input type="button" value="登录" id="btn" / ></div>

</body>

<script type="text/javascript">

    $("#btn").click(function(){

            var u=$("#uid").val();

            var p=$("#pwd").val();

            $.ajax({

                    url:"dlchuli.php",

                    data:{u:u,p:p},

                    type:"POST",

                    dataType:"TEXT",

                    success: function(data){

                            if(data.trim()=="ok"){

                                    window.location.href="main.php";

                                }else{

                                        alert("用户名或密码错误");

                                    }

                        }

                });

        });

</script>

</html>

2.处理页面

<?php

    $u=$_POST['u'];

    $p=$_POST['p'];

    include("./lei/AAA.class.php");

    $db=new AAA();

    $sql="select password from yuangong where username='{$u}'";

    $a=$db->StrQuery($sql);

    if($p!="" && $a==$p ){

            echo "ok";

        }else{

                echo "no";

            }

?>