背景图片预加载

遇到需要加载的图片较多时，可以这样预加载
#preloadedImages { 
       width: 0px; 
       height: 0px; 
       display: inline; 
       background-image: url(path/to/image1.png); 
       background-image: url(path/to/image2.png); 
       background-image: url(path/to/image3.png); 
       background-image: url(path/to/image4.png); 
       background-image: url(); 
}  
<div id="preloadedImages"></div>