+ <td><strong>underlayCallback</strong></td>
+ <td><code>function(canvas, area, dygraph)</code></td>
+ <td><code>null</code></td>
+ <td>When set, this callback gets called before the chart is drawn. It
+ allows you to draw underneath the chart. See the tests for more
+ details on how to use this.
+ <div class="tests">Tests:
+ <a href="tests/underlay-callback.html">underlay-callback</a>
+ <a href="tests/highlighted-region.html">highlighted-region</a>
+ </div>
+ </td>
+ </tr>
+
+ <tr>