A common question is whether you can combine pseudo-classes in any order.
It's important to note that while combining pseudo-classes is typically allowed, there are exceptions. For example, the use of ::selection
is not considered a pseudo-class, but rather a pseudo-element that is not defined in CSS1 or CSS2, nor in any existing specifications. This distinction highlights the limitations of referring to both as "pseudo-selectors," as they serve distinct purposes within CSS.
When writing code, remember that the syntax for pseudo-classes involves a single colon (e.g., :hover
), while pseudo-elements require double colons (e.g., ::selection
). Furthermore, it is crucial to place pseudo-elements at the end of the selector, after any pseudo-classes:
.example:hover::selection { color: red; }
Despite following proper syntax, the effectiveness of using ::selection
may vary across browsers due to its unique behavior.