javascript - Angular cascading dropdowns -

i trying create 2 drop downs 1 topic , other 1 videos. videos 1 going filter topics. thank in advance help.

        <md-input-container flex>             <label>topic</label>             <md-select ng-model="selected.topic" required ng-change="getvideosbytopicid(selected.topic)">                 <md-option ng-repeat="topic in topics" value="{{topic.topicid}}">{{topic.topicname}}</md-option>             </md-select>         </md-input-container>         <md-input-container flex>             <label>video</label>             <md-select ng-model="selected.video" required >                 <md-option ng-repeat="video in videos" value="{{video.videoid}}">{{video.name}}</md-option>             </md-select>         </md-input-container> 

and controller

function getvideosbytopicid(topicid) {     return $http.post(baseurl + 'test/getvideosbytopicid', topicid).then(function (response) {         return $.parsejson(response.data);     }); } 

you can this,

<md-select ng-model="type" >     <md-option ng-value="k" data-ng-repeat="(k,v) in videos">{{ k }}</md-option> </md-select>     <md-select ng-model="metrics" >    <md-option ng-value="t" data-ng-repeat="t in level2">{{ t }}</md-option> </md-select> 

demo