Multiple Drop Down List
<div ng-controller="AppCtrl" layout="column" layout-align="center center" style="min-height: 300px;" class="selectdemoValidations" ng-app="MyApp">
<md-select multiple="{{false}}" placeholder="Pick" ng-model="myModel" ng-change="WhenChanged()">
<md-option value="1">One</md-option>
<md-option value="2">Two</md-option>
<md-option value="3">Three</md-option>
<md-option value="4">Four</md-option>
<md-option value="5">Five</md-option>
<md-option value="6">Six</md-option>
<md-option value="7">Seven</md-option>
<md-option value="8">Eight</md-option>
<md-option value="9">Nine</md-option>
<md-option value="10">Ten</md-option>
<md-option value="11">Eleven</md-option>
<md-option value="12">Twelve</md-option>
<md-option value="13">Thirteen</md-option>
</md-select>
{{myModel}}
<md-button ng-click="clear()">Clear</md-button>
</div>
angular.module('MyApp')
.controller('AppCtrl', function($scope) {
$scope.clear = function(){
$scope.myModel = undefined;
};
$scope.WhenChanged = function(){
alert($scope.myModel);
};
});