title: Angular2 detect OnChange
body: <p>i have code select option on angular2 like this</p>
  
  <pre><code>&lt;div class="form-group"&gt;
      &lt;label for="government"&gt;Provinsi&lt;/label&gt;
      &lt;select class="form-control" name="provinsi" formControlName="provinsi"&gt;
        &lt;option *ngFor="let item of province" value="{{item.id}}" (ngModelChange)="onChange($event)"&gt;{{item.name}}&lt;/option&gt;
      &lt;/select&gt;
    &lt;/div&gt;
    &lt;div class="form-group"&gt;
      &lt;label for="government"&gt;Kabupaten/Kota&lt;/label&gt;
      &lt;select class="form-control" name="kokab" formControlName="kokab"&gt;
        &lt;option *ngFor="let list of regencieslist" value="{{list.id}}" selected="selected"&gt;{{list.name}}&lt;/option&gt;
      &lt;/select&gt;
    &lt;/div&gt;
  </code></pre>
  
  <p>What i want is. if i select the option of Provinsi select form it will trigger some method with value in it. how to trigger method on change with value pass to it</p>
  
  <pre><code>onChange(id){
        this.servicedev.getregencies(id).subscribe(
          regencies =&gt; this.regencieslist = regencies,
          error =&gt; error
        )
      }
  </code></pre>
  
  <p>i wanna trigger the onchange method and pass the value from provinsi select to the id onChange method.</p>