使用ajax的登录页面

<script src="http://www.cnblogs.com/styles/jquery-1.4.min.js" type="text/javascript"></script>
<script type="text/javascript">

$("#login").click(
function()
{
var loginid=document.getElementById("txtloginid");
var psw=document.getElementById("txtpsw");
if(loginid.value=="")
{
alert("请输入您的用户名！");return;
}
if(psw.value=="")
{
alert("请输入您的密码！");return;
}
$.get("http://www.cnblogs.com/common/LoginAjax.aspx?loginid="+loginid.value+"&psw="+psw.value+"&sitecode=cmjjjc", function(data){
if(data!="0")
{
$("#loginform").css("display","none");
$("#resultForm").css("display","block");
$("#userTD").html(data);
loginid.value="";psw.value="";
window.location.href="http://www.cnblogs.com/cmjjjc_xxbs/List/index.htm";

}
else
{
alert("您输入的用户名或者密码错误！");
}
}); 
}
);

 <table width="1002px" border="0" align="center" cellpadding="0" cellspacing="0" bgcolor="#FFFFFF">
        <tr>
            <td style="padding-top: 2px;">
                <table width="1000" height="28" border="0" cellpadding="1" cellspacing="0" class="K_01">
                    <tr>
                        <td width="106">
                            <img src="../images/login.gif" width="106" height="26" /></td>
                        <td width="502" style="padding-left:5px;">
                            <table id="loginform" width="440" border="0" cellspacing="1" cellpadding="1">
                                <tr>
                                    <td>
                                        用户名：</td>
                                    <td>
                                        <input id="txtloginid" type="text" name="textfield4" style=" 120px;" /></td>
                                    <td>
                                        密 码：</td>
                                    <td>
                                        <input id="txtpsw" type="password" name="textfield2" style=" 120px;" /></td>
                                    <td width="10%">
                                        <img src="../images/dl.gif" width="48" height="22" style="cursor:hand;" id="login" /></td>
                                </tr>
                            </table>