Assume E is any element

• A simple selector is one of:
  • * or E followed by one or more [..] (attribute selectors), #id selectors, or pseudo-classes
  • Example: E#fred:hover[class="abc"]
• A selector is:
  • A sequence of simple selectors with whitespace, + (following-sibling) or > (child) between them
  • One pseudo element can be added at the end of the whole sequence (:first-line, :first-letter etc)

div.fred ol > li p + p :first-line

Selects a p element whose immediate sibling before it is a p element. They must be descendants of an li element that is a child of an ol element and the ol element must be a descendant of a div element of class fred. And it only applies to the first line of that p element!

The div.fred way of writing class selectors is only available for XHTML and not XML in general. Similarly the #fred selection of an element with id set to fred