Sets the selected attribute on the element, if the expression inside ngSelected is truthy.
A special directive is necessary because we cannot use interpolation inside the selected
attribute. See the interpolation guide for more info.
<OPTION
  ng-selected="expression">
...
</OPTION>
      | Param | Type | Details | 
|---|---|---|
| ngSelected | expression | 
         If the expression is truthy, then special attribute "selected" will be set on the element  | 
    
<label>Check me to select: <input type="checkbox" ng-model="selected"></label><br/>
<select aria-label="ngSelected demo">
  <option>Hello!</option>
  <option id="greet" ng-selected="selected">Greetings!</option>
</select>