Description

The descendant selector matches all elements that are descendants of a specified element. The first simple selector within this selector represents the ancestor element—a structurally superior element, such as a parent element, or the parent of a parent element, and so on. The second simple selector represents the descendant element we’re trying to match. If you’re a little unclear about the terms ancestor element and descendant element, have a look at CSS Layout and Formatting for a complete explanation.

The combinator we use in a descendant selector is a whitespace character: a space, horizontal tab, carriage return, line feed, or form feed. Since whitespace characters are allowed around all combinators, you can include more than one whitespace character between the simple selectors in a descendant selector.

Consider the following HTML fragment:

<ul>
  <li>Item 1</li>
  <li>
    <ol>
      <li>Sub-item 2A</li>
      <li>Sub-item 2B</li>
    </ol>
  </li>
</ul>

We’ll try to match elements in the above fragment using the selector below:

ul li {
  ⋮ declarations
}

This descendant selector will match all four li elements in the example HTML, because each of those elements has a ul element as its ancestor.

We can also use descendant selectors to match the li elements within the ol in the example above:

ul * li {
  ⋮ declarations
}
ul * * li {
  ⋮ declarations
}
ul * ol li {
  ⋮ declarations
}
ul li * li {
  ⋮ declarations
}
ul ol li {
  ⋮ declarations
}
ul li li {
  ⋮ declarations
}
ul li ol li {
  ⋮ declarations
}

However, there’s no way we can use descendant selectors to match only the list items in the unordered list. To do that, we’d need a child selector.

Compatibility

In Internet Explorer 5.5 and 6, this combinator doesn’t work after a :hover pseudo-class (refer to the aforementioned link for a full explanation of this bug and an appropriate fix).

In Internet Explorer 6 and 7, if there’s only a comment—without any additional whitespace—between two simple selectors, that comment is incorrectly treated as a descendant selector, when in fact it should fail.