客戶端頁面index.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ajax測試用戶名是否存在</title>
<script language="javascript" type="text/javascript">
//生成Http請求對象，用于客戶端向服務/端發送異步的http請求
function getHttpObject()
{
var http;
var browser = navigator.appName;
if(browser == "Microsoft Internet Explorer")
{
//如果用戶使用IE，就返回XMLHTTP的ActiveX對象
http = new ActiveXObject("MSXML2.XMLHTTP.3.0");
}
else
{
//否則返回一個XMLHttpRequest對象
http = new XMLHttpRequest();
}
return http;
}
//獲取全局的HTTP請求對象
var http = getHttpObject();
//處理請求狀態變化
function getHello()
{
//4表示請求已完成
if (http.readyState == 4)
{
//獲取服務段的響應文本
var helloStr = http.responseText;
alert(helloStr);
if(helloStr.charAt(0)!="0")
{alert("用戶名已經存在!");}
else
{alert("用戶名不存在,可以實用!");}
}
}
function HelloWorld()
{
var url = "Check.aspx?id="+document.getElementById("Text1").value;
//指定服務端的地址
http.open("GET", url, true);
//請求狀態變化時的處理函數
http.onreadystatechange = getHello;
//發送請求
http.send(null);
}
</script>
</head>
<body>
<input id="Text1" style="width: 116px" type="text" />
<input id="Button1" type="button" value="button" onclick="javascript：HelloWorld();" />
</body>
</html>
服務器端功能頁面Check.aspx
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class Check : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string str = "select Count(*) from Table where Name=" + Request.QueryString["id"].ToString() + "";
SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=Database;Integrated Security=True");
conn.Open();
SqlCommand cmd = new SqlCommand(str, conn);
int i = (int)cmd.ExecuteScalar();
conn.Close();
Response.Write(i);
}
}
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