title: How to set default value to the field and disable other fields if default value is selected in angularjs
body: <p>I have the following fields- country, state, city, center.</p>
  
  <p>The default value for all the fields is "All".</p>
  
  <p>I am able to enable the fields one by one by using selection of previous field value.</p>
  
  <p>But it is not considering "All" as a value. If it considers then the state is getting activated. So can anyone please help me how to set default value as "All" to all the fields and if "All" is selected then the other fields should be disabled with considering "All" as a value.</p>
  
  <p><strong>My HTML Page :</strong></p>
  
  <pre><code>&lt;div class="col-sm-2 sidenav" style="height:850px;"&gt;
        &lt;div class="well"&gt;
        &lt;form class="form-row " role="form"&gt;
        &lt;div class="form-group"&gt;
            &lt;label class="control-label col-sm-14" for="fName"&gt;Country*&lt;/label&gt;
            &lt;select class="form-control" ng-model="model.selectedCountry" name="country" ng-change="GetCountry(model.selectedCountry)"&gt; 
                 &lt;!--&lt;option value class selected&gt;ALL&lt;/option&gt;--&gt;
                 &lt;option ng-repeat="item in model.countries track by $index" value="{{item}}"&gt;{{item}}&lt;/option&gt;
                     &lt;/select&gt;
            &lt;/div&gt;
            &lt;div class="form-group"&gt;
            &lt;label class="control-label col-sm-20" for="fName"&gt;State*&lt;/label&gt;
            &lt;select class="form-control" ng-model="model.selectedState" name="state" ng-change="GetState(model.selectedState)" ng-disabled="!model.selectedCountry"&gt; 
                 &lt;!--&lt;option value class selected&gt;ALL&lt;/option&gt;--&gt;
                 &lt;option ng-repeat="item in model.states track by $index" value="{{item}}"&gt;{{item}}&lt;/option&gt;
                     &lt;/select&gt;
            &lt;/div&gt;
            &lt;div class="form-group"&gt;
            &lt;label class="control-label col-sm-20" for="fName"&gt;City*&lt;/label&gt;
            &lt;select class="form-control" ng-model="model.selectedCity" name="city" ng-change="GetCity(model.selectedCity)"  ng-disabled="!model.selectedState"&gt; 
                 &lt;!--&lt;option value class selected&gt;ALL&lt;/option&gt;--&gt;
                 &lt;option ng-repeat="item in model.cities track by $index" value="{{item}}"&gt;{{item}}&lt;/option&gt;
                     &lt;/select&gt;
            &lt;/div&gt;
                      &lt;div class="form-group"&gt;
                          &lt;label class="control-label col-sm-20" for="fName"&gt;Center*&lt;/label&gt;
                          &lt;select class="form-control" ng-model="model.selectedCenter" name="center" ng-change="GetCenter(model.selectedCenter)" ng-disabled="!model.selectedCity"&gt;
                          &lt;!--&lt;option value class selected&gt;ALL&lt;/option&gt;--&gt;
                 &lt;option ng-repeat="item in model.centers track by $index" value="{{item}}"&gt;{{item}}&lt;/option&gt;
                          &lt;/select&gt;
                      &lt;/div&gt;
                      &lt;div class="form-group"&gt;
            &lt;label class="control-label col-sm-20" for="fName"&gt;Role*&lt;/label&gt;
            &lt;select class="form-control" ng-model="model.selectedRole" name="city" ng-change="GetRole(model.selectedRole)"  ng-disabled="!model.selectedCountry"&gt; 
                 &lt;!--&lt;option value class selected&gt;ALL&lt;/option&gt;--&gt;
                 &lt;option ng-repeat="item in model.roles track by $index" value="{{item}}"&gt;{{item}}&lt;/option&gt;
                     &lt;/select&gt;
            &lt;/div&gt;
                      &lt;div class="form-group"&gt;
                      &lt;button type="submit" href="#" ng-click="HeadCount()" class="btn btn-primary btn-lg" ng-hide="submitButton" ng-disabled="!model.selectedRole"&gt;SUBMIT&lt;/button&gt;
                      &lt;/div&gt;
              &lt;/form&gt;
          &lt;/div&gt;  
      &lt;/div&gt;
  </code></pre>