Ajax call isn't working

Question

I tried to pass a value to method of controller ( am using codeigniter ) using ajax through jquery. I called the ajax method with in a click event, the click event is working fine, but the ajax is not call. Plz help me. Thanks in advance.

$('#sql_format').click(function(){alert('hi');
    $.ajax({
            url : '<?php echo site_url('adhoc/sql_formater'); ?>',
            data : '',
            type: 'post',
            dataType : 'json',
            success : function(data){
                alert(data);
            }
    });
});

when click the "#sql_format" it displays alert box with 'hi' message. But it doesn't call ajax. Here the adhoc is controller and sql_formater is method.

Controller code

function sql_formater(){
            $sql = $this->input->post('query');

            return $sql;
        }

Answer 1

Try to set all parameters to ajax post like in example, see my answer here

Uploaded File name send through Ajax

  var postData = new FormData();

  $.ajax({
  processData: false, /* important */
  contentType: false, /* important */
  type: "POST",
  url: 'b.php',
  data: postData, /* **  postData */
  error: function(jqXHR, textStatus, errorThrown){ alert(textStatus); }, /* show error */
  success:function(data, textStatus, jqXHR) { alert(data);  },  /* show result*/
  dataType: 'html'  /* I change it ot html for this example*/
  });

Answer 2

Controller code

function sql_formater()
    {
       $sql = $this->input->post('query');
       header('Content-type: application/json');                
       echo json_encode(array("response"=>$sql));
       exit;
    }

And in view

$('#sql_format').click(function(){
    $.ajax({
            url : '<?php echo site_url("adhoc/sql_formater"); ?>',
            data : {'query':'select * from table'},
            type: 'post',
            dataType : 'json',
            success : function(data){
                alert(data.response);
            }
    });
});