你已经知道了，只需要为合适的选择器稍微调整你的 JQuery

You pretty much had it, just needed to adjust your JQuery a little bit for the appropriate selectors

更新小提琴:http://jsfiddle.net/5gsBV/7/

$(document).on("change", ".qty1", function() {
    var sum = 0;
    $(".qty1").each(function(){
        sum += +$(this).val();
    });
    $(".total").val(sum);
});