title: How to get value of <ion-input> in ionic framework?
body: <p>I want value of following input elements so what I should do? 
  </p>
  
  <pre><code>  &lt;ion-item&gt;
      &lt;ion-label floating&gt;Username&lt;/ion-label&gt;
      &lt;ion-input type="text" &gt;&lt;/ion-input&gt;
    &lt;/ion-item&gt;
  
    &lt;ion-item&gt;
      &lt;ion-label floating&gt;Password&lt;/ion-label&gt;
      &lt;ion-input type="password" &gt;&lt;/ion-input&gt;
    &lt;/ion-item&gt;
  &lt;/ion-list&gt;
  </code></pre>