5. Q_ 伪类选择器__checked_将作用与_input_类型为_radio_或者_check

Q: 伪类选择器:checked将作用与input类型为radio或者checkbox,不会作用于option。

A: 不对。

伪类选择器checked的定义很明显:

The :checked CSS pseudo-class selector represents any radio (<input type="radio">), checkbox (<input type="checkbox">) or option (<option>in a <select>) element that is checked or toggled to an on state. The user can change this state by clicking on the element, or selecting a different value, in which case the :checked pseudo-class no longer applies to this element, but will to the relevant one.