html - Allowed child elements of ul

Question

I'm maintaining a legacy app and came across the following code:

<ul>
   <li>...</li>
   <li>...</li>
   <li>...</li>
   <li>...</li>
   <li>...</li>
   <div>
      <li>...</li>
      <li>...</li>
   </div>
</ul>

I've never seen div tags as child elements of ul elements before. The HTML renders fine in browsers.

Is this valid HTML? My gut feeling is that this is strange usage. However, perhaps this is completely normal and valid? Is nesting a div element inside a ul element appropriate usage? Would you recommend for or against this?

Answer 1

It is not valid in any version of HTML, see e.g. HTML 4.01 on ul.

Browsers allow it, though, and parse it so that div becomes a child of ul, and they let you style the div too. This is probably the reason why this markup has been used.