TypeError: this.cont is null

I am trying to use paging methods of DHTLMX tree grid for my salesforce records.
but getting this error.
TypeError: this.cont is null on
dhtmlxtoolbar.js (line 7, col 107)

is there any problem with library.
my code is




<tr> <td><a href="#" OnClick="SelectedVal();"> Selected Value</a></td></tr>

In your code:


Please, make sure that you have this “pagingbox” container on your page.