使用 ng-selected
<select
class="form-control"
ng-model="j.level" convert-to-string>
<option value="-1">请选择课程强度</option>
<option
ng-selected="r.level"
ng-repeat="r in data.levels"
value="{{r.level}}"
ng-bind="r.name">
</option>
</select>
