Background image blurry when scaling on iPad and iPhone

执行css3 tranlate效果时，如果div有zoom，则图片会模糊。
原因有以下三种原因：

1. Scaling a div stretches the pixels and not adding more.
2. background-size: contain; Ensures you that your background-image is fully showen
3. The div never change size.

具体请看

http://stackoverflow.com/questions/6975725/background-image-blurry-when-scaling-on-ipad-and-iphone