JS docs: add cross-reference to Getting Started mobile modal section

javascript.html

@@ -108,6 +108,10 @@ $('#myModal').on('show.bs.modal', function (e) {
       <h4>Overlapping modals not supported</h4>
       <p>Be sure not to open a modal while another is still visible. Showing more than one modal at a time requires custom code.</p>
     </div>
+    <div class="bs-callout bs-callout-warning">
+      <h4>Mobile device caveats</h4>
+      <p>There are some caveats regarding using modals on mobile devices. <a href="{{ page.base_url }}getting-started#mobile-modals">See our browser support docs</a> for details.</p>
+    </div>
 
     <h3>Static example</h3>
     <p>A rendered modal with header, body, and set of actions in the footer.</p>