asp.NetXMLHttpRequestユーザー登録前の検証を実現

 
  
//     ,SEND       
  
function createQueryString() { 
  
var userName = document.getElementById("userName").value; 
  
var querystring = "userName=" + userName; 
  
return querystring; 
  
} 
  
function RunAjax() { 
  
//  '           DEMO1.HTML    XMLHttpRequest     ' 
  
createXMLHttpRequest(); 
  
var queryString = "IsHaveUser.ashx?"; 
  
queryString = queryString + createQueryString() 
  
+ "&timeStamp=" + new Date().getTime();//URL      ，        
  
xmlHttp.onreadystatechange = handleStateChange; 
  
xmlHttp.open("GET", queryString, true); 
  
xmlHttp.send(null); 
  
document.getElementById('validateMessage').innerText = '    ,   ...'; 
  
} 
  
function handleStateChange() { 
  
if (xmlHttp.readyState == 4) { 
  
if (xmlHttp.status == 200) { 
  
var result = xmlHttp.responseText; 
  
document.getElementById("validateMessage").innerText = result; 
  
if (result== "  !    ...") { 
  
setTimeout("document.getElementById('validateMessage').innerText='';", 2000); 
  
} 
  
} 
  
} 
  
} 
  
 
  
 
 

 
  
public class IsHaveUser : IHttpHandler { 
  
public void ProcessRequest (HttpContext context) { 
  
System.Threading.Thread.Sleep(2000); 
  
string userName = context.Request.QueryString["userName"]; 
  
bool result =                   ，     ，     
  
if (result) 
  
{ 
  
context.Response.Write("  !    ..."); 
  
} 
  
else { context.Response.Write("     ,   ..."); } 
  
} 
  
public bool IsReusable { get { return false;}} 
  
}