javascript - only execute function with ng-click if input fields are not empty -

i want perform function if other 2 fields not empty, not sure how it.

ng-click="savetolist($event)"  

html

  <div class="col-xs-5">               <label for="exampleinputpassword1">enter title/description</label>                 <input type="text" id="urlname" class="form-control" placeholder=""  ng-model="mvname" />             </div>             <div class="col-xs-5">                 <label for="exampleinputpassword1">enter url</label>                 <input type="text" id="urllink" class="form-control" placeholder=""  ng-model="mvurl" />           </div>           <div class="col-xs-2">               <a href="javascript:" ng-click="savetolist($event)" class="btn btn-block post">post</a>           </div> 

app.js

$scope.savetolist = function(event) {      var mvname = $scope.mvname.trim();     var mvurl = $scope.mvurl.trim();      if (mvname.length > 0) {       $scope.favurls.$add({         name: mvname,         title: mvurl       });         urlname.value = ''; //urlname id of  input box - angular rocks!       urllink.value = ''; //urlname id of  input box - angular rocks!     }  } 

i error when empty:

error: $scope.mvname undefined 

the problem isn't angular: .trim() doesn't work against undefined values. check see if variable defined before trying trim it, example:

var mvname = ($scope.mvname) ? $scope.mvname.trim() : '' ;