title: Ionic modal firstFocus not working
body: <p>I have an Ionic App that that when a modal launches it suppose to focus the first input. which is the input element with an ID of #discount.</p>
  
  <p>this is my view.</p>
  
  <pre><code>&lt;script id="discount.html" type="text/ng-template"&gt;
  &lt;ion-modal-view&gt;
      &lt;ion-header-bar&gt;
          &lt;h1 class="title"&gt;Add Discount&lt;/h1&gt;
      &lt;/ion-header-bar&gt;
      &lt;ion-content&gt;
          &lt;div class="list list-inset"&gt;
              &lt;label class="item item-input item-stacked-label"&gt;
                  &lt;span class="input-label"&gt;Price&lt;/span&gt;
                  &lt;input type="tel" autofocus class="button-large button-block text-center input-lg" id="discount" ng-model="payment.discountPrice"  ui-money-mask="2" /&gt;
              &lt;/label&gt;
              &lt;br&gt;
              &lt;label class="item item-input item-stacked-label"&gt;
                  &lt;span class="input-label"&gt;Name&lt;/span&gt;
                  &lt;input type="text" class="button-large button-block input-lg" ng-model="payment.discountName" /&gt;
              &lt;/label&gt;
              &lt;br&gt;
              &lt;button class="button button-large button-block button-positive" ng-click="submitDiscount()"&gt;Apply&lt;/button&gt;
              &lt;button class="button button-large button-block button-assertive" ng-click="closeModal()"&gt;Cancel&lt;/button&gt;
          &lt;/div&gt;
      &lt;/ion-content&gt;
  &lt;/ion-modal-view&gt;
  </code></pre>
  
  <p></p>
  
  <p>this is my controller. </p>
  
  <pre><code>    $scope.openDiscountModal = function () {
  
    //cache the modal
    $ionicModal.fromTemplateUrl('discount.html', {
      scope: $scope,
      animation: 'slide-in-up',
      focusFirstInput: true,
      backdropClickToClose: false
    }).then(function (modal) {
      $scope.modal = modal;
      $scope.modal.show().then(document.getElementById('discount').focus());
      console.log('xxx');
    });
  
  };
  </code></pre>
  
  <p>this works fine in the desktop browser but it doesn't focus on my IOS ionic app.</p>