Why do web browsers don't apply the CSS :active state on activation by enter key?

问题

Most web browsers provide keyboard shortcuts to interact with the DOM. e.g.:

Tab shifts the focus to the next focus-able element
Alt + Tab shifts the focus to the previous focus-able element
Enter activates the currently focused element

What I have now figured out is that many popular browsers (Firefox, Chrome, Safari, Internet Explorer) don't apply the CSS :active pseudo-class if an element gets activated by pressing the Enter key.

Why is this so?

I think it is misleading because it looks like you don't trigger the buttons; although you actually do.

回答1:

https://developer.mozilla.org/en-US/docs/Web/CSS/%3Aactive

According to mozilla documentation, the active pseudo class is related to the mouse and the tab key. But there's no mention of the Enter key.

回答2:

According to the CSS Selectors specification:

The :active pseudo-class applies while an element is being activated by the user. For example, between the times the user presses the mouse button and releases it. [...]

So the standard explicitly says that :active should be applied when a user clicks on the element. There is nothing else, so this is not a problem of the browsers, it is a result of a missing standard.

来源：https://stackoverflow.com/questions/32908180/why-do-web-browsers-dont-apply-the-css-active-state-on-activation-by-enter-key