相关疑难解决方法(0)

每当鼠标悬停在只有CSS的图像上时,我就会尝试为图像添加透明的黑色叠加层.这可能吗？我试过这个:

http://jsfiddle.net/Zf5am/565/

但我无法让div出现.

<div class="image">
    <img src="http://www.newyorker.com/online/blogs/photobooth/NASAEarth-01.jpg" alt="" />
    <div class="overlay" />
</div> 

.image {
  position: relative;
  border: 1px solid black;
  width: 200px;
  height: 200px;
}
.image img {
  max-width: 100%;
  max-height: 100%;
}
.overlay {
  position: absolute;
  top: 0;
  left: 0;
  display: none;
  background-color: red;
  z-index: 200;
}
.overlay:hover {
  display: block;
}