This seems to be a really straight forward code, but I cannot figure out why it is not working.
I want to filter the \'model\' dropdown by selected \'make\',
Problem is with your first ngoption, you need to set the model as the value of value property using select as syntax option.value as option..
value
select as
option.value as option.
<select ng-model="makeng" ng-options="option.value as option.display for option in makes">
Plnkr