Ajax簡單應用,檢測使用者名稱是否存在

最後更新：2018-12-05 來源：互聯網

上載者：User

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用戶端頁面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</title>
<script language="javascript" type="text/javascript">
//產生Http請求對象，用於用戶端向服務/端發送非同步http請求
function getHttpObject()
{
var http;
var browser = navigator.appName;

if(browser == "Microsoft Internet Explorer")
{
//如果使用者使用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;
}
//擷取全域的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)
{

//擷取服務段的響應文本

//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>

伺服器端功能頁面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);
}
}

轉自：RelaxMyself 釋放的天空

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