Just another jQuery AJAX not POST parameters correctly - asp.net

Question

I've googled many similar situations, but none of them could solve my problem. Please take a look at my code:
JavaScript:
$.ajax({
type: 'POST',
url: 'alarmInfo.aspx',
data: {request:'BasicGpaInfo'},
dataType: "json",
success: function (data) {
alert(data);
},
error: function () {
alert("Error in loading alarm information!");
}
});
ASP.NET:
protected void Page_Load(object sender, EventArgs e)
{
if (Request.Form["request"] == "BasicGpaInfo")
{
Response.Write(BasicGpaInfo());
}
else
{
Response.Write("Nothing");
}
}
This always returns "Nothing" and break point tells that Request.Form is null. And I have tried with GET and Request.QueryString which gives the same situation.
I guess there's something wrong with data in ajax function and I've tried with the following things that won't help:
data: $.param({request:'BasicGpaInfo'})
data: "{request:'BasicGpaInfo'}"
data: {request:'BasicGpaInfo'}
It won't work on all Web Browsers.
Please give some advice. Thanks!

Answer 1

I tested your code and it runs fine. However it always returns "Error in loading alarm information!" because you are not returning Json from the server.
Javascript is fine, once you return json, it will go into success.
You are returning the whole page, and your ajax method is getting the whole html instead of Json from BasicGpaInfo()
try putting a breakpoint in alert, and you will see all the data come inside data
error: function (data) {
alert("Error in loading alarm information!");
}
alternatively try
error: function (data) {
alert(data);
}
Here is the full code
$.ajax({
type: 'POST',
url: 'Default.aspx/BasicGpaInfoWebMethod',
data: { request: 'BasicGpaInfo' },
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
alert(data);
},
error: function (data) {
alert("Error in loading alarm information!");
//alert(data); // uncomment to see the whole response
}
});
and your webmethod will be :
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public string BasicGpaInfoWebMethod(string request)
{
return request;
}

Answer 2

Try this JSON.stringify before post. For using JSON.stringify in IE<=7 include json2.js file from json.org
$.ajax({
type: 'POST',
url: 'alarmInfo.aspx',
data: JSON.stringify({ request: 'BasicGpaInfo'}),
dataType: "json",
success: function (data) {
alert(data);
},
error: function () {
alert("Error in loading alarm information!");
}
});