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;
          }
      }

}