I am using an ajax call which is as follows

       var ID=$(this).attr('id');
       var input=$("#input_"+ID).val();
       var dataString = {id: ID, value: input}; 
        $("#span_"+ID).html(input);

        if(input.length>0)
        {

            $.ajax({
                type: "POST",
                url: "/apps/worker_app.php",
                data: dataString,
                cache: false,
                success: function(html)
                {
                    $("#span_"+ID).html(span);
                }
            });
        }

How can I get the data in my php function edit_ajax() which is inside worker_app I use post but the array come to be empty

Thanks