Making an Ajax call to the controller - asp.net-mvc

Question

I'm using MVC 2 and trying to make an ajax call to the controller method.
Controller:
[HttpGet]
public ActionResult FirstAjax()
{
return View();
}
[HttpPost]
public ActionResult FirstAjax(string a)
{
return Json("chamara", JsonRequestBehavior.AllowGet);
}
View:
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script type="text/javascript">
$(document).ready(function () {
var serviceURL = '<%= Url.Action("FirstAjax", "AjaxTest") %>';
$.ajax({
type: "POST",
url: serviceURL,
data: param = "",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: successFunc,
error: errorFunc
});
function successFunc(data, status) {
alert(data);
}
function errorFunc() {
alert('error');
}
});
</script>
</head>
In above code please notice my controller. to get the code working i had to add to methods with HTTPPOST and HTTPGET and even the parameter a is not related i just added it because i can not add two methods with the same signature.
I guess this might not be the correct way to do this. please explain the most suitable approach for this kind of code.
UPDATE:
adding a single method with out POST and GET does not work. It just print the string "chamara" on the page.alert not firing
public ActionResult FirstAjax()
{
return Json("chamara", JsonRequestBehavior.AllowGet);
}

Answer 1

From your explanation I think the code what you need is like :
AjaxTestController.cs
[HttpGet]
public ActionResult FirstAjax()
{
return Json("chamara", JsonRequestBehavior.AllowGet);
}
Script:
<script type="text/javascript">
$(document).ready(function () {
var serviceURL = '<%= Url.Action("FirstAjax", "AjaxTest") %>';
$.ajax({
type: "GET",
url: serviceURL,
success: successFunc,
error: errorFunc
});
function successFunc(data) {
alert(data);
}
function errorFunc(xhr, status, err) {
alert('error');
}
});
</script>

Answer 2

Since you cannot have two methods with the same name and signature you have to use the ActionName attribute:
UPDATE:
[HttpGet]
public ActionResult FirstAjax()
{
Some Code--Some Code---Some Code
return View();
}
[HttpPost]
[ActionName("FirstAjax")]
public ActionResult FirstAjaxPost()
{
Some Code--Some Code---Some Code
return View();
}
And please refer this link for further reference of how a method becomes an action. Very good reference though.