title: Cannot make an input type=date required
body: <p>I have two date fields that I would like to make required but it's not adhering to the required attribute I'm placing on the control.  I read another stack post, but he only needed to add the ngModel to the input.  I already have the ngModel included and it's still letting me save without inserting Date.  It's working for my type="text" field...the 'Save' button is disabled until text is entered in the Destination field.  But it's not working for Date.</p>
  
  <pre><code>        &lt;button ion-button text-only [disabled]="itineraryForm.invalid" 
            (click)="saveItinerary()"&gt;
            Save
         &lt;/button&gt;
  
  &lt;ion-content class="cards-bg"&gt;
  &lt;ion-card padding class="ion-cards"&gt;
  &lt;ion-card-content padding&gt;
  &lt;form #itineraryForm="ngForm" (ngSubmit)="saveItinerary()" 
  autocomplete="off"&gt;
  &lt;div class="form-group"&gt;
      &lt;ion-label for="destination"&gt;Destination&lt;/ion-label&gt;
      &lt;input type="text" class="form-control" [(ngModel)]="destination" 
        name="destination" required id="destination" placeholder="Enter 
       destination" #destin&gt;
  &lt;/div&gt;
  &lt;div class="form-group"&gt;
    &lt;ion-label &gt;Trip dates&lt;/ion-label&gt;
      &lt;p style="float: left;"&gt;
        &lt;input type="date" class="form-control" [(ngModel)]="startDate" 
          name="startDate" required id="startDate" placeholder="Start" /&gt;
      &lt;/p&gt;
      &lt;p style="float: right;"&gt;
        &lt;input  type="date" class="form-control" [(ngModel)]="endDate" 
          name="endDate" required id="endDate" placeholder="End"/&gt;
      &lt;/p&gt;
     &lt;/div&gt;
      &lt;/form&gt;
    &lt;/ion-card-content&gt;
    &lt;/ion-card&gt;
   &lt;/ion-content&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/q13ct.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/q13ct.png" alt="enter image description here"></a></p>