Fill arrays from dual list

Hi everyone I want to fill array in data from dual list how I can do it

 $(document).ready(function () {
                $('#btn').click(function () {
                    var listBox = $("#targetListBox").data("kendoListBox");
                    var items = listBox.items();
                   
                    for (var i = 0; i < items.length; i++) {
                        var dataItem = listBox.dataItem(items[i]);
                   
                        alert(dataItem.text);
                    }
               
                });

I have data from targetListBox then I show it in strong textalert I want before show in alert move it to array and show array in alert how I can do that Regards