Jquery.ajax not positioning data correctly in asp.net mvc site - formcollection empty

I am using jquery to submit my form (here the id is #myForm) like this:

$(document).ready(function() {  
        $("#my_form").submit(function(event) {  
            $.ajax(  
          {  
              type: "POST",  
              url: $("#my_form").attr("action"),  
              contentType: "application/json; charset=utf-8",  
              data: ("#my_form").serialize(),  
              success: function(result) {  
                  alert('hi');  
              },  
              error: function(req, status, error) {  
                  alert("Sorry! We could not process the form at this time.");  
              }  
          }  
         );  
         event.preventDefault();  
        });//end submit for my_form  
    });//end document ready  

      

        
        
        
      

    

If I go through the posted data I see the following

POST / PageContents / Edit HTTP / 1.1
x-request-with: XMLHttpRequest
Accept language: ru-us
Referer: [CHANGE ME]
Accept: /
Content-Type: application / json; encoding = UTF-8
Accept-Encoding: gzip, deflate
User-Agent: Mozilla / 4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident / 4.0; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
Host: www.somesite.com:3852
Content-length: 142
Connection: Keep-Alive
Pragma: no-cache

ID = 1 & small_title = Welcome + for !!! & big_title = Chicago !!! & body = here + will be + some + things + for + in + body !!! &. Subtitle = + space + for + pizza !!

But this fails for the correct action because the Request.Forms collection is empty.

If I submit this form without javascript and just use normal HTML, the posted data looks like this:

POST / PageContents / Edit HTTP / 1.1
Accept: image / gif, image / jpeg, image / pjpeg, image / pjpeg, application / x-shockwave-flash, application / x-ms-application, application / x-ms-xbap, application / vnd.ms-xpsdocument, application / xaml + xml, /
Referer: [CHANGE ME]
Accept language: ru-us
User-Agent: Mozilla / 4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident / 4.0 ;. NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
Content-Type: application / x-www-form-urlencoded
Accept-Encoding : gzip, deflate
Host: www.somesite.com:3852
Content-Length: 164
Connection: Keep-Alive
Pragma: no-cache

small_title = Welcome + up to% 21% 21% 21 & big_title = Chicago% 21% 21% 21 & subtitle = + space + for + pizza% 21% 21 & body = here + going + some + things + for + body +% 21% 21% 21 & id = 1

You can see that the data is being laid out correctly so that my routing works and the correct action is called.

All fields in my form do have a name attribute.

Thanks and sorry for the long post.