Get CheckBoxes values to Array or List with Javascripts or Jquery

I want to get values to an array(checkslist) from checked checkboxes. I tried this codes but dont work. in the for I can get "checkslist"s items which is push but, after for it can't. How ı get the all checked CheckBoxes's value to array or list? Please Help

$(function(){

  $("#btnEkle").click(
            function () {

                var checkbox, checkslist, menuId,text,vModel;



                checkslist = [];
                checkbox = document.getElementsByClassName("checks");


                for (var i = 0; checkbox.length; ++i) {
                    if (checkbox[i].checked) {


                        menuId = checkbox[i].value;
                        checkslist.push(menuId);

                    }

                }
            alert(checkslist[0].value )

                     })

})