1//do the edit in your javascript
2
3$('.signinform').submit(function() { 
4   $(this).ajaxSubmit({ 
5       type : "POST",
6       //set the data type
7       dataType:'json',
8       url: 'index.php/user/signin', // target element(s) to be updated with server response 
9       cache : false,
10       //check this in Firefox browser
11       success : function(response){ console.log(response); alert(response)},
12       error: onFailRegistered
13   });        
14   return false; 
15}); 
16
17
18//controller function
19
20public function signin() {
21    $arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);    
22
23   //add the header here
24    header('Content-Type: application/json');
25    echo json_encode( $arr );
26}
27