Develop Reference

jQuery: which is the correct way to post an ajax request with parameter?

My code consists of a ajax request to server where there are parameters to be added to request url. Which is the correct method to implement in jQuery?
var param ="roomNumber="+this.roomNumber+"&roomId="+this.roomId+"&UniqueId="+this.surveyData[this.currentIndex].id+"&optionId="+optId;
or
json data is right way?

In my example I use JSON data format. You can use any your server accepts
$.ajax({
url: 'http://someUrl',
contentType: 'application/json',
data: {
param1: '345345',
param2: 23523
}
}).done(function(result){
//success
}).fail(function(e){
//error
});

Ajax jquery call to GET application/x-javascript

How do I get content of "application/x-javascript" using jquery Ajax call?
As it keep getting me null content.
What I am trying to use for now:
$.ajax({
dataType: "json",
contentType: "application/x-javascript;charset=utf-8",
url:the_url,
async:false,
success:function(r){
console.log("el result" + r) ;
response = r;
}
});

This:
dataType: "json",
tells jQuery to ignore what the server claims it is sending back and to process the result as JSON. JavaScript isn't JSON, so this breaks it.
Remove that line.
Then you should get the data in the success function.
Asides:
This:
contentType: "application/x-javascript;charset=utf-8",
claims you are sending JavaScript. You aren't making a POST request, so you aren't sending anything. Remove it.
Even if you were sending JavaScript to the server, the application/javascript MIME type hasn't been experimental since 2006, so it shouldn't have the x- prefix on it.
async:false, is a terrible idea. It locks up the JS event loop waiting for the response. You shouldn't use it.
response = r;: assigning data to globals is usually a terrible idea. Process the data in the success event handler instead.

Try this out :
$.ajax({
url: 'my/url',
type: 'GET',
data: 'test=mytest&test2=mytest2',
success: function (data) {
console.log(data);
},
error: function (jqXHR, textStatus, errorThrown) {
alert(errorThrown);
}
});
And read the documentation, to see what each parameter is made for :
http://api.jquery.com/jquery.ajax/

jquery ajax : what is the actual request sent?

What is the actual url sent to the server when I use the jquery ajax? And how do I access that value? For example, consider the following code:
<script>
$.ajax({
type: "POST",
dataType: "json",
url: "response.php",
data: {name:'Smith',age:10},
success: function(data) {
...
}
beforeSend: function(){
console.log(url);
// what do I put here to see what is being sent
// I am expecting to see "response.php?name=Smith&age=10"
}
...
So essentially what variable holds "response.php?name=Smith&age=10".
Thanks.

No variable holds
response.php?name=Smith&age=10
because you aren't sending the data as a query string. This would happen if you issued a GET request, but doesn't with a POST request.
You're sending the data in the request body of an HTTP post. The data is the data that you assigned to the data parameter. You don't need to round-trip it through jQuery's ajax methods. You've got it already. It's:
{name:'Smith',age:10}
does jQuery's interpretation of your data really matter?

The settings object is fully populated when beforeSend is called:
beforeSend: function(jqXHR, settings) {
console.log(settings.url);
console.log(settings.data);
}
$.ajax({ type: "POST", ... }) will log
response.php
name=Smith&age=10
and type: "GET"
response.php?name=Smith&age=10
undefined

How do i read simple json result with jquery and how to post new

I built a WCF service which produces JSON. I want to make an external website which uses this webservice. For now I am executing the WCF service over LAN by IIS, so I can connect to the service by going to http://myownaddress/blabla.svc/
I tried to learn some json and to get some results from my service.
For example if I want to use this method:
[OperationContract]
[WebInvoke(Method = "GET",
ResponseFormat = WebMessageFormat.Json,
BodyStyle = WebMessageBodyStyle.Wrapped,
UriTemplate = "json/{id}")]
string JSONData(string id);
I'll go to http://myownaddress/blabla.svc/json/123
And as result I get:
{"JSONDataResult":"You requested product 123"}
Now I have tried to receive this result with the JQuery statement getJSON. But I don't see any results.
My question is how can I get this simple data?
And secondly how can I post data(with javascript) back on to the wcf service is it also possible with json?
-edit-:
I have now updated my code and put this into my document ready function which is located between the <head> <script> .... on my page:
$.getJSON(
'http://myownaddress/blabla.svc',
function(data)
{
alert(data.JSONDataResult);
});
But this won't give the alert with the result. It doesn't even give an alert.. Besides that, in the function I need to give a parameter of id, so for example 123 (look in text above) don't I need to put that in the function also?

To get data use getJSON():
$.getJSON(
'http://myownaddress/blabla.svc/',
function(data) {
alert(data.JSONDataResult);
}
);
To post data you can use this:
$.post('http://myownaddress/postservice.svc', function(data) {
$('.result').html(data);
});
or this (if you need more control):
$.ajax({
type: 'POST',
url: url,
data: data,
success: success,
dataType: dataType
});
You can also use the ajax for getting the data instead of the getJSON method .
UPDATE:
try using ajax method as it gives you more control:
$.ajax({
type: 'GET',
url: "http://myownaddress/blabla.svc/json/123",
success: function(data){alert(data)},
dataType: "json",
complete: function(data){alert(data)},
error: function(jqXHR, textStatus, errorThrown){alert(errorThrown)}
});
Also, if you use firefox, check out firebug extension, it will help you greatly.
If you use chrome then use chrome developer tools.

In order for your to get the json data from a WCF service that is outside your website using Jquery you need to use JSONP.
You can perform the call as shown below:
$.ajax({
url: "http://myownaddress/blabla.svc/",
dataType: "jsonp",
type: "GET",
timeout: 10000,
data: null,
jsonpCallback: "MyCallback",
success: function (data, textStatus, jqXHR) {
alert(action.toLowerCase());
},
error: function (jqXHR, textStatus, errorThrown) {alert('error is:' + errorThrown);
},
complete: function (jqXHR, textStatus) {alert('complete');
}
});
JSONP is used when you want to perform a cross domain calls using Javascript.
Also your WCF service should be compatible to handle JSONP calls by injecting the results to the response stream using the callBack method specified in the URL.

Do you have your code like this ?
$.getJSON(
'http://myownaddress/blabla.svc/',
function(result) {
alert(result.JSONDataResult);
}
);
Remember getJSON will not immediately return you the data, you have to make use of the result in a callback function.

Why did you change your url?
$.getJSON(
'h t t p://myownaddress/blabla.svc' ==> 'h t t p://myownaddress/blabla.svc/123',
function(data)
{
alert(data.JSONDataResult);
});

How to get a value from a JSON hash

In a jquery ajax call I get sent back some JSON from the server and want to use some of it in the success callback. I pass in the data, but how do I get at a specific value (say "id")?
I tried this but I get undefined:
success : function(data) {
alert(data["id"]);
},

Your ajax request should look something like this:
$.ajax({
url: "...",
dataType: "json",
success: function(data){
alert(data.id);
});