title: angular2 submit form by pressing enter without submit button
body: <p>Is it possible to submit a form that does not have submit button (by pressing enter) 
  example : </p>
  
  <pre><code>&lt;form [ngFormModel]="xxx" (ngSubmit)="xxxx()"&gt;
    &lt;input [(ngModel)]="lxxR"   ngControl="xxxxx"/&gt;
  &lt;/form
  </code></pre>