How to display the contents of a frame?

Question

selenium

There is a floating frame. How to display the elements of the "stationary" part with nested floating elements to check if a certain entry is present on the page or not?

<tbody id="topbody"> постоянная часть
<tr>
<tr class="odd"> плавающая часть
<tr class="even"> плавающая часть
</tbody>

I need to check the content of nested floating elements. To understand whether the expected element is displayed or not.

плавающая часть может иметь начинку типа
<tr class="odd">
<td>username</td>
<td>some_other_text</td>
</tr>

how to find let's say by the name "username"