daterangepicker get var in field

I have a longer list of date fields as below

<input id="date_declaration8_185" activite_dmc8_id="386" class="form-control date_declaration8" name="date_declaration" type="text" value="">

<input id="date_declaration8_266" activite_dmc8_id="256" class="form-control date_declaration8" name="date_declaration" type="text" value="">

I would like to be able to recover the value of the attribute activite_dmc8_id and send with date

$('.date_declaration8').daterangepicker({
            "opens": "center",
            "drops": "up",
            "singleDatePicker": true,
            "showDropdowns": true,
            "showWeekNumbers": true,
            "maxSpan": {
                "days": 7
            }
        }, function(start, end, label,) {

            var id = $(this).attr('activite_dmc8_id');

            dataString = {
                id: id,
                date_declaration:  start.format('YYYY-MM-DD'),
                rend_selected:$('#rend_selected8_'+id).val(),
                quantite:$('#quantite8_'+id).val(),
                valeur:$('#valeur8_'+id).val(),
                notes: $('#notes8_' + id).val(),
                num_parcelle: $('#num_parcelle8_' + id).val()

            };
            var message='';
            $.ajax({
                type: "POST",
                url: "",
                headers: {'X-CSRF-TOKEN': ''},
                data: dataString,
                cache: false,
                success: function(xhr){

                    getChieldactiviteListeDMC();

                    new Noty({
                        type:"success",
                        layout:"topRight",
                        text:"Mise à jour ",
                        progressBar:true,
                        timeout:2500,
                        animation:{
                            open:"animated bounceInRight",
                            close:"animated zoomOutRight"
                        }
                    }).show();

                },
                error: function(xhr, status, error) {

                    var err = JSON.parse(xhr.responseText);
                    $.each(err.errors, function(name2, val2) {
                        message = message+"<br />"+val2;
                    });
                    new Noty({
                        type:"warning",
                        layout:"topRight",
                        text:"Hey this is an warning notification.",
                        progressBar:true,
                        timeout:2500,
                        animation:{open:"animated bounceInRight",close:"animated zoomOutRight"}
                    }).show();

                }
            });

        });

I cannot use the field id, but I cannot get the value of activite_dmc8_id of the field calling datpicker

I imagine that you have to pass the value in parameterizing the function but I don't know how to do it

thank you for your help, I am struggling with this problem and cannot find a solution.

PS: Sorry for my approximate English

via Chebli Mohamed