图片加载完毕再淡入

<a href="#" class="box">
<img class="img" src="loadimg.jpg" onload="this.style.opacity=1;" style="opacity: 1;">
</a>

.box{
position: relative;
width: 126px;
height: 82px;
background: #e8e8e8;
}

.img{
width: 100%;
height: 100%;
opacity: 0;
-webkit-transition-duration: .4s;
transition-duration: .4s;
-webkit-transition-property: opacity;
transition-property: opacity;
}