javascript - angular-ui-mask doesn't mask as expected in the text box -

i using angular web-application , trying use angular-ui-mask (https://github.com/angular-ui/ui-mask) mask input prevent typing numbers in text box. i've tried doc suggested cannot put use. here textbox code snippet.

<div class="form-group"><label class="col-sm-2 control-label">memo</label>   <div class="col-sm-10">     <input type="text" class="form-control" ui-mask="99-999-9999" ng-model="vm.textfield">   </div> </div> 

not sure if missing or need add in controller. clue ?

perhaps forgot load script files...

<script type="text/javascript" src="bower_components/angular/angular.js"></script> <script type="text/javascript" src="bower_components/angular-ui-mask/dist/mask.js"></script> 

...or add module dependencies?

angular.module('myapp', ['ui.mask', ...]) 

edit: put minimal working plunker.