CSS：悬停转换后

Question

HTML结构

<div id="small_gal">
    <div><img src="images1.jpg" /></div>
    <div><img src="images1.jpg" /></div>
    <div><img src="images1.jpg" /></div>
    <div><img src="images1.jpg" /></div>
    <div><img src="images1.jpg" /></div>
    <div><img src="images1.jpg" /></div>
    <div><img src="images1.jpg" /></div>
    <div><img src="images1.jpg" /></div>
</div>

图像有阴影，所以border不是解决方案，因为它会在图像之外

边框正在转换，它可以在FF上顺利运行，但不能在Chrome或其他浏览器中运行

这是我用过的代码

#small_gal div:hover{cursor: pointer;}
#small_gal div:after {
    content: '';
    position: absolute;
    width: 112px;
    height: 81px;
    border: 3px solid #e27501;
    left: 9px; top: 9px;
    z-index: 9;

    opacity: 0;
    -webkit-transition: opacity 0.5s ease-in-out;
    -moz-transition: opacity 0.5s ease-in-out;
    -o-transition: opacity 0.5s ease-in-out;
    -ms-transition: opacity 0.5s ease-in-out;
    transition: opacity 0.5s ease-in-out;
}
#small_gal div:hover:after {
    opacity: 1;
}

注意：

#small_gal

只是容器 每个图像都包含在div中，因此我们可以实现：在

之后

Answer 1

Firefox 4+是唯一支持转换:before和:after等伪元素的浏览器。

来源：http://css-tricks.com/13555-transitions-and-animations-on-css-generated-content/

Answer 2

CSS过渡在WebKit中仍然是实验性的，所以你很可能遇到了涉及:: after伪选择器的一些边缘案例错误。我建议完全避免它，而只是转换border-color。这在Chrome和Safari中运行良好：

#small_gal div.p {
    border: 2px solid transparent;
    -webkit-transition: border-color 1s ease-in;
}

#small_gal div.p:hover {
    border-color: orange;
}

Answer 3

如果您可以在元素本身上定义属性并在伪元素中使用inherit，则可以对伪元素使用CSS转换，如：before和：after。因此，在您的情况下，您可以在opacity上进行转换，而不是在border-color上进行转换。

*, *:before, *:after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

#small_gal div {
  border-color: transparent;
  cursor: pointer;
  display: inline-block;
  position: relative;
  -webkit-transition: border-color 0.5s ease-in-out;
  -moz-transition: border-color 0.5s ease-in-out;
  -o-transition: border-color 0.5s ease-in-out;
  -ms-transition: border-color 0.5s ease-in-out;
  transition: border-color 0.5s ease-in-out;
}
#small_gal div:after {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  border-color: inherit;
  border-style: solid;
  border-width: 3px;
  left: 0;
  top: 0;
}
#small_gal div:hover {
  border-color: #e27501;
}
#small_gal div img {
  display: block;
  height: auto;
  max-width: 150px;
  width: auto;
}

<div id="small_gal">
    <div><img src="//c2.staticflickr.com/6/5826/23633880170_4bb8492de8_z.jpg" /></div>
    <div><img src="//c2.staticflickr.com/6/5826/23633880170_4bb8492de8_z.jpg" /></div>
    <div><img src="//c2.staticflickr.com/6/5826/23633880170_4bb8492de8_z.jpg" /></div>
    <div><img src="//c2.staticflickr.com/6/5826/23633880170_4bb8492de8_z.jpg" /></div>
    <div><img src="//c2.staticflickr.com/6/5826/23633880170_4bb8492de8_z.jpg" /></div>
</div>