title: bootstrap daterangepicker open by button
body: <p>i use the bootstrap daterangepicker (dangrossman) and Bootstrap 3.
  Now i want does i can the daterangepicker open with a addon-button and with clickling in the input field</p>
  
  <p>my code:</p>
  
  <pre><code>&lt;div class="form-group"&gt;
          &lt;div class="input-group input-group-sm"&gt;
              &lt;span class="input-group-btn"&gt;
                  &lt;button class="btn btn-default" type="button"&gt;&lt;span class="glyphicon glyphicon-calendar"&gt;&lt;/span&gt;&lt;/button&gt;
              &lt;/span&gt;
                  &lt;input id="daterangepicker" class="form-control" type="text" name="daterangepickerDisplay"&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>This works.. but only when i click in the inputfield..</p>