I think I’m pretty good with HTML. So when I discover that I’m wrong about something, I’m pretty taken aback. In my defense, I don’t think I’m alone in being wrong.
Take a look at this page about HTML lists. It’s a nice, pretty page. Its makers clearly know what they’re doing. But notice what it has to say about nested lists. They say that you can nest lists. Like so:
<ul> <li>Item 1</li> <ul> <li>Sub-item 1</li> </ul> <li>Item 2</li> </ul>
I’ve been writing HTML code like that ever since I was a child programmer back in 1996. Turns out, it’s not legal HTML, according to the 4.01 spec. The only sub-element to a list is the list item element. You can’t put an unordered list inside another unordered list.
This is legal:
<ul> <li>Item 1 <ul> <li>Sub-item 1</li> </ul> </li> <li>Item 2</li> </ul>
In this case, the nested list is, itself, contained in the first list item.