if-and-only-if element

常見例句

雙語例句

• Only one pseudo-element may appear per selector, and if present it must appear after the sequence of simple selectors that represents the subjects of the selector.
  一個選擇器只能使用一個偽元素，并且偽元素必須處于選擇器語句的最后。
返回 if-and-only-if element