login page using jquery ajax with asp.net ?

var username = $("#txtusername").val();

var password = $("txtpassword").val();

$.ajax({

type: "POST",

url: "login.aspx",

data: "action=" + "Login" + "&username=" + username + "&password=" +password,

success: function (msg) {

if (msg == "true") {

window.location.href = 'Index.aspx';

}else{

alert("Username or password is incorrect");

}

});

c# Code in Page load funtion

if (Request["action"] == "login")

{

LoginUser();

Response.End();

}

private void LoginUser()

{

string userName = Request["userName"];

string password = Request["password"];

if (obj != null)

{

Response.Write("true");

}

else

{

Response.Write("notPresent");

}