ajax+jsp无刷新验证的用户存在问题,来者加分
<script language="JavaScript">
function createxmlhttprequest()
{
var xmlhttp=false;
try
{
xmlhttp=new ActiveXObject('Msxm12.XMLHTTP');
}
catch(e)
{
try
{
xmlhttp=new ActiveXObject('Microsoft.XMLHTTP');
}
catch(e)
{
try
{
xmlhttp=new XmlHttpRequest();
}
catch(e)
{
}
}
}
return xmlhttp;
}
function checkuser()
{
var xmlhttp=createxmlhttprequest();
var username=document.getElementById('txtName');
xmlhttp.open('get','CheckUserIs.jsp?UserName='+username.value);
xmlhttp.onreadystatechange=function()
{
if(xmlhttp.readyState==4)
{
if(xmlhttp.status==200)
{
if(xmlhttp.responseText=="1")
{
document.getElementById("IsOkUserName").innerText='该用已存在';
}
else
{
document.getElementById("IsOkUserName").innerText='可以注册';
}
}
}
}
xmlhttp.send(null);
}
</script>
那么Jsp部分的代码应该怎么写呢
<%
String UserName = request.getParameter("username");
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con = DriverManager.getConnection("jdbc:odbc:myDs","sa","");
PreparedStatement pst = con.prepareStatement("select FirstName from Employees where FirstName =? ");
pst.setString(1,UserName);
ResultSet rs= pst.executeQuery();
if(rs.next())
{
////如何返回值
}
else
{
//如何返回值
}
}
catch(Exception ex)
{
System.out.println(ex);
}
%>