下划线js _grouby浏览器差异

Question

我看到一些奇怪的行为与正在呈现选择的optgroups和选项的顺序有关。我有一些数据用于在select中构建optgroup，然后使用下划线js _grouby函数进行选项。 Firefox以我订购json的方式呈现数据，Chrome和IE以相反的顺序显示它。

Here's a Fiddle

HTML：

 <select name="dropdownlist" id="dropdownlist">
   <option value="All">All</option>
 </select>

JavaScript的：

 $(document).ready(function() {
 var dataresults = [{"MonthName":"April","Month":4,"Year":2014,"Date":"\/Date(1397451600000)\/"},{"MonthName":"January","Month":1,"Year":2014,"Date":"\/Date(1388556000000)\/"},{"MonthName":"November","Month":11,"Year":2013,"Date":"\/Date(1384322400000)\/"},{"MonthName":"July","Month":7,"Year":2013,"Date":"\/Date(1373864400000)\/"}];

 BindYearDropDown(dataresults);

 function BindYearDropDown(data)
    {
        var groupData = _.groupBy(data, function (obj) {
            return obj.Year;
        });

        var optGroups = [];
        for (var key in groupData) {
            if (groupData.hasOwnProperty(key)) {
                var optGroup = $("<optgroup></optgroup>");
                optGroup.attr("label", key);
                optGroup.attr("id", key);
                var currentGroup = groupData[key];
                for (var i = 0; i < currentGroup.length; i++) {
                    $("<option />").attr("value", currentGroup[i].Month).html(currentGroup[i].MonthName).appendTo(optGroup);
                }
                optGroups.push(optGroup);
            }
        }
        //optGroups.reverse();
        for (var i = 0; i < optGroups.length; i++) {
            $('#dropdownlist').append(optGroups[i]);
        }
    };

FireFox结果:(这就是我想要显示数据的方式）

Chrome结果：

IE11结果：

提前致谢，

KC

Answer 1

如果您真的想使用您提供的结构中的数据，可以创建一个年份列表，然后对其进行排序。否则，我建议@mu建议太短。 jsfiddle

/* reusable descending sort function */
function sortDescending(value) {
  return value * -1;
};

     ...
     var groupData = _.groupBy(data, function (obj) {
         return obj.Year;
     });

     /* Sort the years in descending order */
     var years = _.sortBy(_.keys(groupData), sortDescending);

     var optGroups = [];
     for (var index in years) {
         var key = years[index];
     ...