addPhoto()调用后，.wrap的perspective属性就没效果了？

.wrap{
    perspective: 800px;
    -webkit-perspective: 800px;
    -moz-perspective: 800px;
}
.photo-wrap{
    position: absolute;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    -webkit-transform-style: preserve-3d;
    /*-moz-transform-style: preserve-3d;*/
    transition:all .6s ease-out;
}

function addPhotos() {
   var template=get('#wrap').innerHTML;
   var html=[];
   for(var i in data){
       var _html=template
           .replace('{{index}}',i)
           .replace('{{caption}}',data[i].caption)
           .replace('{{img}}',data[i].img)
           .replace('{{desc}}',data[i].desc)
       html.push(_html)
   }
   get('#wrap').innerHTML=html.join('');
}
addPhotos();

此函数调用后，卡片翻转就没有3d效果了，只是平面压缩效果，这是为啥？