获得焦点时-图片抖动

css

#out{
    widows: 100px;
    height: 100px;
    background: black;
    transition: all 1s;
}
#out:hover{
    animation:dong 1s ease-in-out 0s 1 normal;
    -moz-animation:dong 1s ease-in-out 0s 1 normal;
    -webkit-animation:dong 1s ease-in-out 0s 1 normal;
    -o-animation:dong 1s ease-in-out 0s 1 normal;
}
@keyframes dong{
    0%{
        transform: rotate(20deg);
    }
    30%{
        transform: rotate(-20deg)
    }
    70%{
        transform: rotate(20deg)
    }
    100%{
        transform: rotate(-20deg)
    }
}

html

<div id="out">
</div>