how to make empty rows as high as those non-empty rows?

Question

<table id="experiences" cellpadding="0" border="1" width="100%">
    <caption>table name</caption>
    <tr><th>col1</th><th>col2</th><th>col3</th><th>col4</th><th>col5</th><th>col6</th></tr>
    <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
    <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
    <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
    <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
</table>

The above doesn't meet the requirements.

Answer 1

Put an   in the blank ones.