Javascript 是否将默认值设置为ng选项中的第一个？

好的，我有这个：

    scope.$watch('item', function(){
        var getmonthdrop = scope && scope.item  && scope.item.month;
        var getyeardrop = scope && scope.item  && scope.item.Year;
       // scope.month = getmonthdrop;
       // scope.year = getyeardrop;
       console.log( getmonthdrop + '-' + getyeardrop);
    });
scope.monthpicker = function(alldatesdumparray){

var alldatesdump = booking.getalldates();
var alldatesdumparray = $.map(booking.getalldates(), function(value, index) {
    var dropdates = new Date(value.date);
    var dropdate = dropdates.getDate();
    var month=new Array();
month[0]="January";
month[1]="February";
month[2]="March";
month[3]="April";
month[4]="May";
month[5]="June";
month[6]="July";
month[7]="August";
month[8]="September";
month[9]="October";
month[10]="November";
month[11]="December";
    var dropmonth = month[dropdates.getMonth()];
    var checkmonth = dropdates.getMonth();
    var dropyear = dropdates.getFullYear();
    var joindates = dropmonth + '-' + dropyear;
    var monthyear = checkmonth + '- '
    var today = new Date();
    var mm = today.getMonth(); //January is 0!
    var yyyy = today.getFullYear();

    if(mm < checkmonth && dropyear < yyyy){

    }else{
        value.date = joindates;
        value.month = checkmonth;
        value.Year =  dropyear;
        return [value];
    }
});
//console.log(alldatesdumparray);
    var dupes = {};
    var singles = [];
$.each(alldatesdumparray, function(i, el) {
    if (!dupes[el.date]) {
        dupes[el.date] = true;
        singles.push(el);
        return singles;
    }
});
/*scope.item = singles[0] && singles[0].date; 
console.log(scope.item);
console.log(singles[0]);*/
return singles;
};
//console.log(monthpicker(singles));
//scope.item = {scope.monthpicker[0].value};

使用此html：

<select ng-model="item" ng-options="o as o.date for o in monthpicker(singles)"></select>

它始终返回null的第一个值： 像这样：

<select ng-model="item" ng-options="o as o.date for o in monthpicker(singles)" class="ng-pristine ng-valid">
    <option value="?" selected="selected"></option>
    <option value="0">January-2014</option>
    <option value="1">February-2014</option>
    <option value="2">March-2014</option>
    <option value="3">April-2014</option>
    <option value="4">May-2014</option>
    <option value="5">June-2014</option>
    <option value="6">July-2014</option>
    <option value="7">August-2014</option>
    <option value="8">September-2014</option>
    <option value="9">October-2014</option>
    <option value="10">November-2014</option>
    <option value="11">December-2014</option>
</select>

---

如何分配项以使选项中的第一个值可用

您可以将ng选项中的值指定给select的ng模型$socpe.item

在控制器中：

$scope.item=月[0]