Why the :before and :after pseudo-elements work only in Firefox?

Question

I\'ve created a select list with options having :after and :before pseudo-elements - DEMO

Answer 1

Whether there is a restriction is undefined, hence the inconsistent behavior. This is mentioned at the bottom of the relevant section in the spec:

Note. This specification does not fully define the interaction of :before and :after with replaced elements (such as IMG in HTML). This will be defined in more detail in a future specification.

Most HTML form elements are considered replaced elements, including select and option.