用AJAX编写用户注册实例

ASP.NET Ajax用户名注册验证

<asp:TextBox ID="txtUserName" runat="server" onBlur="send_request('addAdmin');"></asp:TextBox>






//script处理函数

<script language="javascript" type="text/javascript">
function send_request(flag)
{
//创建XMLHttpRequest;
http_request = false;
if(window.XMLHttpRequest)
{
//　非IE　浏览器
http_request = new XMLHttpRequest();
}
else if(window.ActiveXObject)
{
//IE
try
{
http_request = new ActiveXObject("Msxml2.XMLHTTP");//较新版本的IE
}catch(e)
{
try
{
http_request = new ActiveXOBject("Microsoft.XMLHTTP");//旧版本IE
}catch(e){}
}
}
else
{
window.alert("不能创建　XMLHttpRequest对象，无法应用Ajax");
return false;
}
//指定回调函数
if(flag == "addAdmin")
{
http_request.onreadystatechange = addAdmin;
//创建HTTP请求
http_request.open("get","Handler.ashx?flag=addAdmin&userName="+document.getElementById("txtUserName").value,true);

}
else if(flag == "updateTitle")
{
http_request.onreadystatechange = updateTitle;
//创建HTTP请求
i = document.getElementById("ddlVoteTitle").selectedIndex;//选择的索引
id = document.form1.ddlVoteTitle.options[i].value;
http_request.open("get","Handler.ashx?flag=updateTitle&id="+id,true);

}

//发送上面创建的HTTP请求
http_request.send(null);
}
function addAdmin()
{
if(http_request.readyState == 4)//发送成功
{
if(http_request.status == 200)//交易成功
{
//正式处理有信息
if(http_request.responseText == "该用户已经存在")
{
//隐藏提交按扭
document.getElementById("Button1").style.display ="none";
}
else
{
document.getElementById("Button1").style.display="";
}

document.getElementById("lblShow").innerText=http_request.responseText;
}
}
}
function updateTitle()
{
if(http_request.readyState == 4)//发送成功
{
if(http_request.status == 200)//交易成功
{
//正式处理有信息

document.getElementById("lblTitle").innerText=http_request.responseText;
}
}
}
</script>

//创建一般处理程序

//Handler.ashx

<%@ WebHandler Language="C#" Class="Handler" %>

using System;
using System.Web;

public class Handler : IHttpHandler {

DB DBManager = new DB();

public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "text/plain";

string flag = context.Request.QueryString["flag"].ToString();

if (flag.Equals("addAdmin"))
{

string userName = context.Request.QueryString["userName"].ToString();
string strSql = "select count(*) from admin where userName = '" + userName + "'";

if (Convert.ToInt32(DBManager.executeGetReturn(strSql)) > 0)
{
context.Response.Write("该用户已经存在");
}
else
{
context.Response.Write("你可以注册［" + userName + "］");
}
}
else if (flag.Equals("updateTitle"))
{
int id = Convert.ToInt32(context.Request.QueryString["id"].ToString());
string strSql = "update voteConfig set id=" + id;
if (DBManager.executeNonQuery(strSql) > 0)
{
context.Response.Write("设置已成功，当前系统前调查［" + DBManager.executeGetReturn("select voteTitle from voteMaster where id=" + id) + "］");
}
else
{
context.Response.Write("设置失败");
}
}
}

public bool IsReusable {
get {
return false;
}
}

}