Rowspan is not working correctly, what can I do to achieve this?

Question

I cannot get this table to accept rowspan for some reason.

I haven't tried much.

<table style="border: 3px solid black; width:95%">
            <caption>This is a caption, looks a lot like a 
title</caption>
            <colspan>
                <col style="background-color:aquamarine">
                <col style="background-color:crimson">
                <col style="background-color:aquamarine">
            </colspan>
            <thead>
                <tr>
                    <th colspan="2">This is a colspan.</th>
                    <th rowspan="3">rowspan</th>
                </tr>
            </thead>
            <tbody>
                <tr>
                    <td>Test1</td>
                    <td>Test2</td>
                </tr>
            </tbody>
            <tfoot>
                <tr>
                    <td>Test3</td>
                    <td>Test4</td>
                </tr>
            </tfoot>
        </table>

I want rowspan="3" to work correctly.

Answer 1

If I understood the question correctly, you want to have rowspan for rows including header.

<table style="border: 3px solid black; width:95%">
            <caption>This is a caption, looks a lot like a 
title</caption>
            <colspan>
                <col style="background-color:aquamarine">
                <col style="background-color:crimson">
                <col style="background-color:aquamarine">
            </colspan>
            <tbody>
                <tr>
                    <th colspan="2">This is a colspan.</th>
                    <th rowspan="3">rowspan</th>
                </tr>           
                <tr>
                    <td>Test1</td>
                    <td>Test2</td>
                </tr>
                <tr>
                    <td>Test3</td>
                    <td>Test4</td>
                </tr>
            </tbody>
           
        </table>

Is it what you are expecting ?