css 背景图片居中显示

经常用到css中背景图片居中显示，记录下，直接上代码：

[code]  height: 100%;width: 100%;background-image: url(\"图片地址\");background-repeat: no-repeat;background-position-x: center;background-position-y: center;background-size: 100% 100%;

如果要保持图片的宽高比，将 background-size: 100% 100%; 改成 background-size: contain;