Did I make mistake?

Everytime I do request.getParameter("dataString"); ----> inside my JSP processor

it always returned me NULL.

Actually I do posting the variable dataString with a value;

Take a look at this my jquery;

(correct me if I'm wrong);

2. var content;
3. var dataString="ha";
4. 
   
5. $( function() {
6. 
   
7.     $.validator.addMethod("username", function(value, element) {
8.         return this.optional(element) || /^[a-z0-9\_]+$/i.test(value);
9.     }, "UserID: only letters, numbers, or underscore.");
10. 
    
11.     $('#userAccountForm').validate();
12. 
    
13.     $('input').focus( function() {
14.         content = $(this).val();
15.         if(content=='- none -') {
16.             $(this).val("");
17.         }
18.     } );
19.     
20.     $('input').blur( function() {
21.         content = $(this).val();
22.         if(content=='') {
23.             $(this).val("- none -");
24.         }
25.     } );
26. 
    
27.     var options = {
28.         target: "#result",
29.         url: "user-form-function",
30.         beforeSubmit: validate,
31.         data: dataString,
32.         success: getResponse
33.     };
34. 
    
35.     $('#userAccountForm').ajaxForm(options);
36. 
    
37. } );
38. 
    
39. function validate(formData, jqForm, options){
40. 
    
41.     var emptyThing = "- none -";
42. 
    
43.     // ensure all fields are not empty
44.     // we use word - none - as empty field
45.     var usName = $('#username').val();
46.     var email = $('#email').val();
47.     var contc = $('#mobilephone').val();
48.     //    var photo = $('#avatar').val();
49.     var usId = $('#userid').val();
50.     var pass = $('#password').val();
51.     var editClient = $('input:radio[name=editClient]:checked').val();
52.     var addClient = $('input:radio[name=addClient]:checked').val();
53.     var delClient = $('input:radio[name=deleteClient]:checked').val();
54.     var adminPriv = $('input:radio[name=adminPriv]:checked').val();
55.     
56.     if(adminPriv==undefined){
57.         alert("it is not admin okay?");
58.         adminPriv = "staff";
59.     } else {
60.         adminPriv = "administrator";
61.     }
62. 
    
63.     if(usName==emptyThing){
64.         usName = "none";
65.     }
66.     if(contc==emptyThing){
67.         contc = "0";
68.     }
69.     if(pass==emptyThing){
70.         pass = "default";
71.     }
72.     
73.     dataString = "username="+usName+"&"+"contact="+contc+"&"+"email="+email+"&"+"userid="+usId+"&"+"password="+pass+"&"+"editclient="+editClient+"&"+"addclient="+addClient+"&"+"deleteclient="+delClient+"&"+"adminprivillege="+adminPriv;
74. 
    
75.     // animate
76.     $('#userAccountForm').fadeOut(1000, function(){
77.         $('#loadingBar').show();
78.         $('#loadingBar').fadeIn("slow");
79.     } );
80. 
    
81.     return true;
82. }
83. 
    
84. function getResponse(html){
85.     $('#loadingBar').fadeOut(500);
86.     $('#result').html(html).show();
87.     alert("in getting response");
88. }