What is the opposite of :hover (on mouse leave)?

问题:

Is there any way to do the opposite of :hover using only CSS? As in: if :hover is on Mouse Enter, is there a CSS equivalent to on Mouse Leave?

Example:

I have a HTML menu using list items. When I hover one of the items, there is a CSS color animation from #999 to black. How can I create the opposite effect when the mouse leaves the item area, with an animation from black to #999?

jsFiddle

(Have in mind that I do not wish to answer only this example, but the entire "opposite of :hover" issue.)

回答1:

If I understand correctly you could do the same thing by moving your transitions to the link rather than the hover state:

ul li a {
    color:#999;       
    transition: color 0.5s linear; /* vendorless fallback */
    -o-transition: color 0.5s linear; /* opera */
    -ms-transition: color 0.5s linear; /* IE 10 */
    -moz-transition: color 0.5s linear; /* Firefox */
    -webkit-transition: color 0.5s linear; /*safari and chrome */
}

ul li a:hover {
    color:black;
    cursor: pointer;
}

http://jsfiddle.net/spacebeers/sELKu/3/

The definition of hover is:

The :hover selector is used to select elements when you mouse over them.

By that definition the opposite of hover is any point at which the mouse is not over it. Someone far smarter than me has done this article, setting different transitions on both states - http://css-tricks.com/different-transitions-for-hover-on-hover-off/

#thing {
   padding: 10px;
   border-radius: 5px;

  /* HOVER OFF */
   -webkit-transition: padding 2s;
}

#thing:hover {
   padding: 20px;
   border-radius: 15px;

  /* HOVER ON */
   -webkit-transition: border-radius 2s;
}

回答2:

Just use CSS transitions instead of animations.

A {
    color: #999;
    transition: color 1s ease-in-out;
}

A:hover {
    color: #000;
}

Live demo

回答3:

No there is no explicit property for mouse leave in CSS.

You could use :hover on all the other elements except the item in question to achieve this effect. But Im not sure how practical that would be.

I think you have to look at a JS / jQuery solution.

回答4:

You can use CSS3 transition

Some good links:

http://css-tricks.com/different-transitions-for-hover-on-hover-off/

http://www.alistapart.com/articles/understanding-css3-transitions/

回答5:

You have misunderstood :hover; it says the mouse is over an item, rather than the mouse has just entered the item.

You could add animation to the selector without :hover to achieve the effect you want.

Transitions is a better option: http://jsfiddle.net/Cvx96/

回答6:

The opposite of :hover appears to be :link.

(edit: not technically an opposite because there are 4 selectors :link, :visited, :hover and :active. Five if you include :focus.)

For example when defining a rule .button:hover{ text-decoration:none } to remove the underline on a button, the underline shows up when you roll off the button in some browsers. I've fixed this with .button:hover, .button:link{ text-decoration:none }

This of course only works for elements that are actually links (have href attribute)

回答7:

Although answers here are sufficient, I really think W3Schools example on this issue is very straightforward (it cleared up the confusion (for me) right away).

Use the :hover selector to change the style of a button when you move the mouse over it.

Tip: Use the transition-duration property to determine the speed of the "hover" effect:

Example

.button {
    -webkit-transition-duration: 0.4s; /* Safari & Chrome */
    transition-duration: 0.4s;
}

.button:hover {
    background-color: #4CAF50; /* Green */
    color: white;
}

In summary, for transitions where you want the "enter" and "exit" animations to be the same, you need to employ transitions on the main selector .button rather than the hover selector .button:hover. For transitions where you want the "enter" and "exit" animations to be different, you will need specify different main selector and hover selector transitions.