Why does this call to jQuery's $.ajax() fire an empty request in Chrome and Firefox?

Question

Hello,

I am trying to call a WCF RESTful service from jQuery. I am using JSON to encode both request and response.

The following code functions correctly in IE8:

url = 'http://ipv4.fiddler:5683/WeatherWCF/NewBinding/MyService/GetValueFloat';

$.ajax({
       url: url,
       data: '{"alias": "Udetemperatur"}',
       type: "POST",
       contentType: "application/json; charset=utf-8",
       dataType: "text",  // not "json" we'll parse
       success:
               function(res) {
                   alert('Received response: ' + res);
                   }
   });

However, in both Firefox and Chrome, res contains an empty string. After using Fiddler to monitor the request, it appears that jQuery sends an empty request to the server as shown in this screen dump: http://imgur.com/EJgwS.png
This is the successful request: http://imgur.com/S77BA.png

What am I doing wrong?

Kind regards,

Martin

Answer 1

http://ipv4.fiddler:5683. Due to security policies cross domain ajax requests are not allowed. In FireFox use FireBug to see exactly what's sent to the server and what's the response.

Answer 2

First check Darin Dimitrov's answer. Then consider using dataType: "jsonp" to make cross domain calls which return json data.

Check the jQuery.ajax documentation for more information

Answer 3

Try changing the name of the Url variable..

either

myurl = 'http://ipv4.fiddler:5683/WeatherWCF/NewBinding/MyService/GetValueFloat';

$.ajax({
       url: myurl ,

or put quotes around the key name ..

url = 'http://ipv4.fiddler:5683/WeatherWCF/NewBinding/MyService/GetValueFloat';

$.ajax({
       'url': url,