backspace key press on Jquery ui Autocomplete textbox doesn't remove any letters on it?

backspace key press on Jquery ui Autocomplete textbox doesn't remove any letters on it?

This is my text field for which i am uisng Autocomplete .


  1.       <input type="text" name="state" id="state"  placeholder="State" maxlength="25" required onkeypress="return nospecialCharacters(event)"/>


    $("#state").autocomplete({
      source: function(request, response) {
        var statevalue = $.trim($("#state").val());
        if (statevalue) {
          $.ajax({
            url: url + 'eee',
            dataType: 'jsonp',
            jsonp: false,
             timeout: 6000,
            jsonpCallback: 'jsonCallback',
               delay: 100,
            success: function(data) {
     $("#state").empty();
              response(data);
            }
          });
        }
      },
      minLength: 2,
        appendTo: "#state_result",
             select: function (event, ui) {
       $("#state").val(ui.item.label);
                   $("#city").focus();
                  return false;
              },
                    close: function(event, ui)
     $(this).data().term = null;
    });


Everything works fine , but the issue i am facing is that when some selection is made on the textinput and try to do a backspace , it doesn't remove any characters (I guess its making requests , so it keep on updating the box)

Could you please let me know  how to resolve this ??