add submit validations to template driven form code example

Example 1: ngForm

<form #f="ngForm" (ngSubmit)="onSubmit(f)" novalidate>
  <input name="first" ngModel required #first="ngModel">
  <input name="last" ngModel>
  <button>Submit</button>
</form>

<p>First name value: {{ first.value }}</p>
<p>First name valid: {{ first.valid }}</p>
<p>Form value: {{ f.value | json }}</p>
<p>Form valid: {{ f.valid }}</p>

Example 2: angular html input validation template driven

content_copy
      
      <input id="name" name="name" class="form-control"
      required minlength="4" appForbiddenName="bob"
      [(ngModel)]="hero.name" #name="ngModel" >

<div *ngIf="name.invalid && (name.dirty || name.touched)"
    class="alert alert-danger">

  <div *ngIf="name.errors.required">
    Name is required.
  </div>
  <div *ngIf="name.errors.minlength">
    Name must be at least 4 characters long.
  </div>
  <div *ngIf="name.errors.forbiddenName">
    Name cannot be Bob.
  </div>

</div>