为什么谷歌下是3D，火狐是2D显示

#d{

-webkit-perspective:800;

-webkit-perspective-origin:50% 50%;

-webkit-transform-style: -webkit-preserve-3d;

-moz-perspective:800;

-moz-perspective-origin:50% 50%;

-moz-transform-style: -moz-preserve-3d;}

#block{width:500px;height:500px;background-color:yellow;margin:100px auto ;

-webkit-transform:rotateX(45deg);

-moz-transform:rotateX(45deg);}

</style>

<div id="d">

   <div id="block"></div>

</div>