Ajax實(shí)現(xiàn)異步刷新驗(yàn)證用戶名是否已存在的具體方法_

1、Ajax實(shí)現(xiàn)異步刷新驗(yàn)證用戶名是否已存在的具體方法_ 由于要做一個(gè)注冊(cè)頁(yè)面，看到很多網(wǎng)站上都是用法Ajax異步刷新驗(yàn)證用戶名是否可用的，所以自己也動(dòng)手做一個(gè)小實(shí)例 都是簡(jiǎn)潔的實(shí)例，所以挺直發(fā)代碼 靜態(tài)頁(yè)面Ajax.html 代碼如下: html head titleAjax/title script type=text/javascript function loadXMLDoc() if (document.getElementById(account).value = ) document.getElementById(accDiv).innerHTML = 用戶名不能為空; return

2、; var xmlHttp; if(window.XMLHttpRequest) / code for IE7+ xmlHttp = new XMLHttpRequest(); else / code for IE5/IE6 xmlHttp = new ActiveXObject(Microsoft.XMLHTTP); xmlHttp.onreadystatechange = function () if (xmlHttp.readyState = 4 xmlHttp.status = 200) /document.getElementById(myDiv).innerHTML=xmlHttp

3、.responseText; if (xmlHttp.responseText = true) document.getElementById(accDiv).innerHTML = 用戶名不行用; else document.getElementById(accDiv).innerHTML = 用戶名可用; var a = document.getElementById(account).value; / get xmlHttp.open(GET, validate.aspx?account= + a + random= + Math.random, true); xmlHttp.send(

4、); function delData() document.getElementById(account).value = ; document.getElementById(accDiv).innerHTML = ; /script /head body h3ajax/h3 table tr td賬號(hào)：/tdtdinput id=account type=text onblur=loadXMLDoc(); onfocus=delData();/tdtddiv id=accDiv/div/td /tr tr td密碼：/tdtdinput id=passwd type=password /t

5、d /tr tr td確認(rèn)密碼：/tdtdinput id=vPasswd type=password /td /tr tr td姓名：/tdtdinput id=name type=text /td /tr /table /body /html 在賬號(hào)輸入框失去焦點(diǎn)時(shí)調(diào)用函數(shù) 訪問(wèn)服務(wù)器用法的是Get方法，所以在參數(shù)處用法了附加隨機(jī)碼來(lái)避開(kāi)緩存。 驗(yàn)證頁(yè)面validate.aspx后臺(tái)代碼： 代碼如下: using System; using System.Collections.Generic; using System.Linq; using System.Web; using Syst

6、em.Web.UI; using System.Web.UI.WebControls; using System.Configuration; using System.Data.Sql; using System.Data.SqlClient; public partial class Ajax_validate_validate : System.Web.UI.Page public SqlConnection conn; protected void Page_Load(object sender, EventArgs e) Response.Clear(); if (Exists(Re

7、quest.QueryStringaccount) Response.Write(true); else Response.Write(false); Response.End(); / summary / 獵取數(shù)據(jù)庫(kù)連接 / /summary / returns/returns protected SqlConnection GetConnection() string str = ConfigurationManager.ConnectionStringsConnectionString.ConnectionString; conn = new SqlConnection(str); re

8、turn conn; protected bool Exists(string account) using (GetConnection() try conn.Open(); string sqlStr = select count(*) from userinfo where account= + account + ; SqlCommand cmd = new SqlCommand(sqlStr, conn); int row = Convert.ToInt32(cmd.ExecuteScalar(); if (row 0) return true; else return false; catch (Exception e) throw e; finally conn.Close(); 在后臺(tái)中驗(yàn)證用戶名是否已經(jīng)存在于數(shù)據(jù)庫(kù)中，返回真或者假 數(shù)據(jù)庫(kù)很