AngularJS null value for select

You can use the ngOptions directive on the select. According to the documentation:

Optionally, a single hard-coded <option> element, with the value set to an empty string, can be nested into the <select> element. This element will then represent the null or "not selected" option. See example below for demonstration.

<select ng-model="obj.selected" ng-options="key as label for (key, label) in ['No', 'Yes']">
  <option value="">Unknown</option>
</select>

It's obviously a better idea to define the options list directly in the controller.

Try using ng-options instead of manually creating tags, as in this example, lightly-edited from the Angular docs:

http://plnkr.co/edit/DVXwlFR6MfcfYPNHScO5?p=preview

The operative parts here are lines 17, defining a 'colors' object, and the ng-options attributes iterating over those colors to create options.

This should work for you:

Controller:

  function MyCntrl($scope) {
    $scope.obj ={"selected":null};
    $scope.objects = [{id: 1, value: "Yes"}, {id: 0, value: "No"}]
  }

Template:

  <div ng-controller="MyCntrl">

    <select ng-model="obj.selected"
            ng-options="value.id as value.value for value in objects">
            <option value="">Unknown</option>
    </select>

<br/>
     {{obj}}
  </div>

Working plnkr

You should use ng-options with select.