ajax验证登录注册

<form id="form1" onsubmit="return false;">
<table id="login-table">
<tr>
<td width="60">学号：</td>
<td><input class="textbox" type="text" style="width:160px;" id="txtUserName"
maxlength="9" onblur="checkUserName()" onclick="$.trim(this.value)"/><span></span>
</td>
</tr>
<tr>
<td width="60">密码：</td>
<td><input class="textbox" type="password" style="width:160px;" id="txtUserPwd"
onblur="checkUserPwd()" onclick="$.trim(this.value)" /><span></span>
</td>
</tr>
<tr>
<td width="60">验证码：</td>
<td><input class="textbox" type="text" style="width:160px;" maxlength="5"
id="txtCheckCode" onblur="checkCheckCode()" onclick="$.trim(this.value)"/><span>
</span>
</td>
</tr>
<tr>
<td width="60"></td>
<td><div style="color:#808080;">输入下图中的字符，不区分大小写</div><br />
<img src="CheckCode.aspx" style="vertical-align:middle;" alt="验证码" id="imgCheckCode" />
<a href="#" id="change_image">看不清，换一张</a></td>
</tr>
<tr>
<td width="60"></td>
<td><input type="image" src="App_Themes/Images/btn_login.jpg" id="btnLogin"
alt="马上登录" style="border:0;"/></td>
</tr>
</table>
</form>

<script language="javascript" type="text/javascript" >
$(document).ready(function(){
// 验证码更新
$('#change_image').click(
function(){
$('#imgCheckCode').attr('src','CheckCode.aspx?'+Math.random());
});
//关键的代码
$("#btnLogin").click(function(){
if(checkUserName() && checkUserPwd() && checkCheckCode())
{
var data = {
UserName: $('#txtUserName').val(),
UserPwd: $('#txtUserPwd').val(),
CheckCode: $('#txtCheckCode').val()
};
//提交数据给Login.ashx页面处理
$.post("Ajax/Login.ashx",data,function(result){
if(result == "1") //登录成功
{
alert("登录成功！您可以进行其他操作了！");
// 关闭模拟窗口
window.parent.window.jBox.close();
}
else if(result == "2") //验证码错误
{
$('#txtCheckCode').next("span").css("color","red").text("*
验证码错误");
}
else
{
alert("登录失败！请重试");
}
});
}
else
{
checkUserName();
checkUserPwd();
checkCheckCode();
}
});
});

//check the userName
function checkUserName()
{
if($("#txtUserName").val().length == 0)
{
$("#txtUserName").next("span").css("color","red").text("*用户名不为空");
return false;
}
else
{
var reg = /^\d{9}$/;
if(!reg.test($('#txtUserName').val()))
{
$('#txtUserName').next("span").css("color","red").text("*正确的格式
如：030602888");
return false;
}
else
{
$("#txtUserName").next("span").css("color","red").text("");
return true;
}
}
}
//check the pwd
function checkUserPwd()
{
if($('#txtUserPwd').val().length == 0)
{
$('#txtUserPwd').next("span").css("color","red").text("*密码不为空");
return false;
}
else
{
$('#txtUserPwd').next("span").css("color","red").text("");
return true;
}
}
// check the check code
function checkCheckCode()
{
if($('#txtCheckCode').val().length == 0)
{
$('#txtCheckCode').next("span").css("color","red").text("*验证码不为空");
return false;
}
else
{
$('#txtCheckCode').next("span").css("color","red").text("");
return true;
}
}