Nested treegrid

[ivaaaan]

I'm trying make nested treegrids but get error: Uncaught TypeError: Cannot read property 'getChildNodes' of undefined

Code:

<table class="tree">
            <tr class="treegrid-1">
                <td>ID</td>
                <td>Client</td>
                <td>Date</td>
                <td>Status</td>
            </tr>
            <tr class="treegrid-2 treegrid-parent-1">
                <td colspan="7">
                    <table class="tree table table-bordered">
                        <tr class="treegrid-6">
                           <td>Test</td>
                        </tr>
                        <tr class="treegrid-11 treegrid-parent-6">
                            <td>Test2</td>
                        </tr>
                    </table>
                </td>
            </tr>
</table>