jQuery 1.7以后 jQuery2 新元素绑定事件on替代live

//定义一个类别改变的事件hander
        function classChangeHander() {
            var thisinput = $(this);
            thisinput.parent().nextAll().remove();
            if (thisinput.val().trim() == "") {
                return;
            }
            $.get("{:U(‘Admin/Item/getChildClass‘)}", {‘class_id‘: thisinput.val()}, function (data) {
                if (data.length) {
                    var optionStr = ‘<option value="">&nbsp;</option>‘;
                    data.forEach(function (item) {
                        optionStr += ‘<option value="‘ + item.class_id + ‘">‘ + item.class_name + ‘</option>‘;
                    });
                    var thisDepth = thisinput.data(‘depth‘) + 1;
                    thisinput.parent().after("<div class=‘col-sm-2‘><select class=‘form-control‘ id=‘class_" + thisDepth + "‘ name=‘class_id‘ data-depth=‘" + thisDepth + "‘>" + optionStr + "</select></div>");
                    var newId = ‘class_‘ + thisDepth;
                    $("select[id^=" + newId + "]").on("change", classChangeHander);//绑定子类别的事件
                }
            }, ‘json‘);
        }
        //class
        $("select[id^=‘class_‘]").on("change", classChangeHander);//默认加载的时候绑定父类别下拉框的事件