Checkpoints and countermeasures when COLSPAN does not work

If you use the colspan attribute on the td element of a table and the effect does not appear, it may be due to CSS style settings that are causing unintended behavior. In particular, if display: flex; is applied to the td element, colspan may not work. This article details why colspan does not work and what to do about it.

Causes of colspan not working

When a td element has display: flex;, it stops acting as a table cell and acts as a container with Flexbox characteristics. As a result, table-specific attributes such as colspan and rowspan are ignored and the expected layout is not applied.

Concrete examples

<table>
  <tr>
    <td style="display: flex;" colspan="2">The colspan doesn't work for this cell.</td>
  </tr>
</table>

In the above example, the effect of colspan="2" is ignored because display: flex; is applied to td.

Countermeasure when colspan does not work

To solve this problem, instead of applying display: flex; to the td element itself, it is effective to create a wrapper element inside the table cell and set display: flex; to the wrapper. This allows the td element to flexibly control the internal layout while maintaining its function as a table cell.

Example of solution code

<table>
  <tr>
    <td colspan="2">
      <div style="display: flex;">
        <span>This cell works colspan</span>
        <span>Adjustable internal layout</span>
      </div>
    </td>
  </tr>
</table>

The above code adds a div inside the td element and applies display: flex; to that div. This way, the colspan functionality is retained, plus the internal layout can be adjusted with Flexbox.

Other checkpoints

Style parent elements: Check that the display property is not also set for the parent table or row ( tr). Unintentional changes to the display properties of a table or row can affect the behavior of the entire table.
CSS resets: Make sure that any CSS resets or frameworks you are using are not interfering with the display properties of the table. In particular, CSS resets may apply display: block; or display: flex; to td or th elements.

Conclusion

Many of the reasons why colspan does not work are due to the application of Flexbox, which changes the behavior of table cells. To solve the problem, it is recommended to set display: flex; not on the td element itself, but on its inner elements. This method allows both table layout and flexible internal layout. While keeping the table structure correct, review the CSS settings for optimal layout.